Literatura académica sobre el tema "Eruptive fluxes"
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Artículos de revistas sobre el tema "Eruptive fluxes"
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Linan, L., É. Pariat, G. Aulanier, K. Moraitis y G. Valori. "Energy and helicity fluxes in line-tied eruptive simulations". Astronomy & Astrophysics 636 (abril de 2020): A41. http://dx.doi.org/10.1051/0004-6361/202037548.
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Context. Conservation properties of magnetic helicity and energy in the quasi-ideal and low-β solar corona make these two quantities relevant for the study of solar active regions and eruptions. Aims. Based on a decomposition of the magnetic field into potential and nonpotential components, magnetic energy and relative helicity can both also be decomposed into two quantities: potential and free energies, and volume-threading and current-carrying helicities. In this study, we perform a coupled analysis of their behaviors in a set of parametric 3D magnetohydrodynamic (MHD) simulations of solar-like eruptions. Methods. We present the general formulations for the time-varying components of energy and helicity in resistive MHD. We calculated them numerically with a specific gauge, and compared their behaviors in the numerical simulations, which differ from one another by their imposed boundary-driving motions. Thus, we investigated the impact of different active regions surface flows on the development of the energy and helicity-related quantities. Results. Despite general similarities in their overall behaviors, helicities and energies display different evolutions that cannot be explained in a unique framework. While the energy fluxes are similar in all simulations, the physical mechanisms that govern the evolution of the helicities are markedly distinct from one simulation to another: the evolution of volume-threading helicity can be governed by boundary fluxes or helicity transfer, depending on the simulation. Conclusions. The eruption takes place for the same value of the ratio of the current-carrying helicity to the total helicity in all simulations. However, our study highlights that this threshold can be reached in different ways, with different helicity-related processes dominating for different photospheric flows. This means that the details of the pre-eruptive dynamics do not influence the eruption-onset helicity-related threshold. Nevertheless, the helicity-flux dynamics may be more or less efficient in changing the time required to reach the onset of the eruption.
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Segonne, Charlotte, Nathalie Huret, Sébastien Payan, Mathieu Gouhier y Valéry Catoire. "A Spectra Classification Methodology of Hyperspectral Infrared Images for Near Real-Time Estimation of the SO2 Emission Flux from Mount Etna with LARA Radiative Transfer Retrieval Model". Remote Sensing 12, n.º 24 (16 de diciembre de 2020): 4107. http://dx.doi.org/10.3390/rs12244107.
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Fast and accurate quantification of gas fluxes emitted by volcanoes is essential for the risk mitigation of explosive eruption, and for the fundamental understanding of shallow eruptive processes. Sulphur dioxide (SO2), in particular, is a reliable indicator to predict upcoming eruptions, and its systemic characterization allows the rapid assessment of sudden changes in eruptive dynamics. In this regard, infrared (IR) hyperspectral imaging is a promising new technology for accurately measure SO2 fluxes day and night at a frame rate down to 1 image per second. The thermal infrared region is not very sensitive to particle scattering, which is an asset for the study of volcanic plume. A ground based infrared hyperspectral imager was deployed during the IMAGETNA campaign in 2015 and provided high spectral resolution images of the Mount Etna (Sicily, Italy) plume from the North East Crater (NEC), mainly. The LongWave InfraRed (LWIR) hyperspectral imager, hereafter name Hyper-Cam, ranges between 850–1300 cm−1 (7.7–11.8 µm). The LATMOS (Laboratoire Atmosphères Milieux Observations Spatiales) Atmospheric Retrieval Algorithm (LARA), which is used to retrieve the slant column densities (SCD) of SO2, is a robust and a complete radiative transfer model, well adapted to the inversion of ground-based remote measurements. However, the calculation time to process the raw data and retrieve the infrared spectra, which is about seven days for the retrieval of one image of SO2 SCD, remains too high to infer near real-time (NRT) SO2 emission fluxes. A spectral image classification methodology based on two parameters extracting spectral features in the O3 and SO2 emission bands was developed to create a library. The relevance is evaluated in detail through tests. From data acquisition to the generation of SO2 SCD images, this method requires only ~40 s per image, which opens the possibility to infer NRT estimation of SO2 emission fluxes from IR hyperspectral imager measurements.
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Calvari, Sonia, Gaetana Ganci, Sónia Victória, Pedro Hernandez, Nemesio Perez, José Barrancos, Vera Alfama et al. "Satellite and Ground Remote Sensing Techniques to Trace the Hidden Growth of a Lava Flow Field: The 2014–2015 Effusive Eruption at Fogo Volcano (Cape Verde)". Remote Sensing 10, n.º 7 (12 de julio de 2018): 1115. http://dx.doi.org/10.3390/rs10071115.
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Fogo volcano erupted in 2014–2015 producing an extensive lava flow field in the summit caldera that destroyed two villages, Portela and Bangaeira. The eruption started with powerful explosive activity, lava fountains, and a substantial ash column accompanying the opening of an eruptive fissure. Lava flows spreading from the base of the eruptive fissure produced three arterial lava flows. By a week after the start of the eruption, a master lava tube had already developed within the eruptive fissure and along the arterial flow. In this paper, we analyze the emplacement processes based on observations carried out directly on the lava flow field, remote sensing measurements carried out with a thermal camera, SO2 fluxes, and satellite images, to unravel the key factors leading to the development of lava tubes. These were responsible for the rapid expansion of lava for the ~7.9 km length of the flow field, as well as the destruction of the Portela and Bangaeira villages. The key factors leading to the development of tubes were the low topography and the steady magma supply rate along the arterial lava flow. Comparing time-averaged discharge rates (TADR) obtained from satellite and Supply Rate (SR) derived from SO2 flux data, we estimate the amount and timing of the lava flow field endogenous growth, with the aim of developing a tool that could be used for hazard assessment and risk mitigation at this and other volcanoes.
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Cox, Daniel, Sebastian F. L. Watt, Frances E. Jenner, Alan R. Hastie, Samantha J. Hammond y Barbara E. Kunz. "Elevated magma fluxes deliver high-Cu magmas to the upper crust". Geology 48, n.º 10 (10 de junio de 2020): 957–60. http://dx.doi.org/10.1130/g47562.1.
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Abstract Porphyry Cu-Au ore deposits are globally associated with convergent margins. However, controls on the processing and distribution of the chalcophile elements (e.g., Cu) during convergent margin magmatism remain disputed. Here, we show that magmas feeding many Chilean stratovolcanoes fractionate sulfides with a high-Cu/Ag ratio early in their crustal evolution. These magmas show evidence of lower-crustal garnet and amphibole crystallization, and their degree of sulfide fractionation and Cu depletion increase with both crustal thickness and the extent of garnet fractionation. However, samples from a small proportion of volcanoes with elevated eruptive fluxes depart from this Cu-depleting trend, instead erupting Cu-rich magmas. This implies that at these atypical sites, elevated magma productivity and crustal throughput, potentially facilitated by “pathways” exploiting major crustal fault systems, enable rapid magma transit, avoiding lower-crustal Cu-depleting sulfide fractionation and potentially playing an important role in porphyry ore genesis.
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Parkhomov, Vladimir, Victor Eselevich y Maksim Eselevich. "Geoeffectiveness of an Eruptive Prominence". System Analysis & Mathematical Modeling 4, n.º 2 (26 de octubre de 2022): 123–51. http://dx.doi.org/10.17150/2713-1734.2022.4(2).123-151.
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The study examined a chain of phenomena from the Sun to the Earth, which allows to study the mechanism of geoeffectiveness of eruptive prominences propagating from the Sun inside the CME (coronal mass ejections). An eruptive prominence ejected into the solar wind moves with its speed towards the Earth in the form of a DSEP (diamagnetic structure of an eruptive prominence). The contact of the DSEP with the magnetosphere leads to its compression and the passage of the DSEP substance into the magnetosphere. The duration of a magnetospheric disturbance in the form of polar auroras on the dayside, a global amplification of current systems, an increase in charged particle fluxes in the radiation belts, and the generation of irregular pulsations of the Pi2-3 type is determined by the duration of the DSEP. A diagram of the geoeffectiveness of the DSEP has been constructed. The resulting scheme is confirmed by statistical studies of the DSEP in different years of solar activity.
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Liu, Yang, Brian T. Welsch, Gherardo Valori, Manolis K. Georgoulis, Yang Guo, Etienne Pariat, Sung-Hong Park y Julia K. Thalmann. "Changes of Magnetic Energy and Helicity in Solar Active Regions from Major Flares". Astrophysical Journal 942, n.º 1 (1 de enero de 2023): 27. http://dx.doi.org/10.3847/1538-4357/aca3a6.
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Abstract Magnetic free energy powers solar flares and coronal mass ejections, and the buildup of magnetic helicity might play a role in the development of unstable structures that subsequently erupt. To better understand the roles of energy and helicity in large flares and eruptions, we have characterized the evolution of magnetic energy and helicity associated with 21 X-class flares from 2010 to 2017. Our sample includes both confined and eruptive events, with 6 and 15 in each category, respectively. Using the Helioseismic and Magnetic Imager vector magnetic field observations from several hours before to several hours after each event, we employ (a) the Differential Affine Velocity Estimator for Vector Magnetograms to determine the photospheric fluxes of energy and helicity, and (b) nonlinear force-free field extrapolations to estimate the coronal content of energy and helicity in source-region fields. Using superposed epoch analysis, we find, on average, the following: (1) decreases in both magnetic energy and helicity, in both photospheric fluxes and coronal content, that persist for a few hours after eruptions, but no clear changes, notably in relative helicity, for confined events; (2) significant increases in the twist of photospheric fields in eruptive events, with twist uncertainties too large in confined events to constrain twist changes (and lower overall twist in confined events); and (3) on longer timescales (event time +12 hr), replenishment of free magnetic energy and helicity content to near preevent levels for eruptive events. For eruptive events, magnetic helicity and free energy in coronal models clearly decrease after flares, with the amounts of decrease proportional to each region’s pre-flare content.
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Layana, Susana, Felipe Aguilera, Germán Rojo, Álvaro Vergara, Pablo Salazar, Juan Quispe, Pablo Urra y Diego Urrutia. "Volcanic Anomalies Monitoring System (VOLCANOMS), a Low-Cost Volcanic Monitoring System Based on Landsat Images". Remote Sensing 12, n.º 10 (16 de mayo de 2020): 1589. http://dx.doi.org/10.3390/rs12101589.
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The practice of monitoring active volcanoes, includes several techniques using either direct or remote measurements, the latter being more important for volcanoes with limited accessibility. We present the Volcanic Anomalies Monitoring System (VOLCANOMS), a new, online, low-cost and semiautomatic system based on Landsat imagery. This system can detect permanent and/or temporal thermal anomalies in near-infrared (NIR), short-wave infrared (SWIR), and thermal infrared (TIR) bands. VOLCANOMS allows researchers to calculate several thermal parameters, such as thermal radiance, effective temperature, anomaly area, radiative, gas, convective, and total heat, and mass fluxes. We study the eruptive activity of five volcanoes including Krakatau, Stromboli, Fuego, Villarrica and Lascar volcanoes, comparing field and eruptive data with thermal radiance. In the case of Villarrica and Lascar volcanoes, we also compare the thermal radiance and eruptive activity with seismic data. The thermal radiance shows a concordance with the eruptive activity in all cases, whereas a correlation is observed between thermal and seismic data both, in Villarrica and Lascar volcanoes, especially in the case of long-period seismicity. VOLCANOMS is a new and powerful tool that, combined with other techniques, generates robust information for volcanic monitoring.
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Delle Donne, Dario, Alessandro Aiuppa, Marcello Bitetto, Roberto D’Aleo, Mauro Coltelli, Diego Coppola, Emilio Pecora, Maurizio Ripepe y Giancarlo Tamburello. "Changes in SO2 Flux Regime at Mt. Etna Captured by Automatically Processed Ultraviolet Camera Data". Remote Sensing 11, n.º 10 (20 de mayo de 2019): 1201. http://dx.doi.org/10.3390/rs11101201.
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We used a one-year long SO2 flux record, which was obtained using a novel algorithm for real-time automatic processing of ultraviolet (UV) camera data, to characterize changes in degassing dynamics at the Mt. Etna volcano in 2016. These SO2 flux records, when combined with independent thermal and seismic evidence, allowed for capturing switches in activity from paroxysmal explosive eruptions to quiescent degassing. We found SO2 fluxes 1.5–2 times higher than the 2016 average (1588 tons/day) during the Etna’s May 16–25 eruptive paroxysmal activity, and mild but detectable SO2 flux increases more than one month before its onset. The SO2 flux typically peaked during a lava fountain. Here, the average SO2 degassing rate was ~158 kg/s, the peak emission was ~260 kg/s, and the total released SO2 mass was ~1700 tons (in 3 h on 18 May, 2016). Comparison between our data and prior (2014–2015) results revealed systematic SO2 emission patterns prior to, during, and after an Etna’s paroxysmal phases, which allows us to tentatively identify thresholds between pre-eruptive, syn-eruptive, and post-eruptive degassing regimes.
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Kazachenko, Maria D. "A Database of Magnetic and Thermodynamic Properties of Confined and Eruptive Solar Flares". Astrophysical Journal 958, n.º 2 (16 de noviembre de 2023): 104. http://dx.doi.org/10.3847/1538-4357/ad004e.
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Abstract Solar flares sometimes lead to coronal mass ejections that directly affect Earth's environment. However, a large fraction of flares, including on solar-type stars, are confined flares. What are the differences in physical properties between confined and eruptive flares? For the first time, we quantify the thermodynamic and magnetic properties of hundreds of confined and eruptive flares of GOES class C5.0 and above, 480 flares in total. We first analyze large flares of GOES class M1.0 and above observed by the Solar Dynamics Observatory, 216 flares in total, including 103 eruptive and 113 confined flares, from 2010 until 2016 April; we then look at the entire data set of 480 flares above class C5.0. We compare GOES X-ray thermodynamic flare properties, including peak temperature and emission measure, and active-region (AR) and flare-ribbon magnetic field properties, including reconnected magnetic flux and peak reconnection rate. We find that for fixed peak X-ray flux, confined and eruptive flares have similar reconnection fluxes; however, for fixed peak X-ray flux confined flares have on average larger peak magnetic reconnection rates, are more compact, and occur in larger ARs than eruptive flares. These findings suggest that confined flares are caused by reconnection between more compact, stronger, lower-lying magnetic fields in larger ARs that reorganizes a smaller fraction of these regions’ fields. This reconnection proceeds at faster rates and ends earlier, potentially leading to more efficient flare particle acceleration in confined flares.
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Corradini, Stefano, Lorenzo Guerrieri, Dario Stelitano, Giuseppe Salerno, Simona Scollo, Luca Merucci, Michele Prestifilippo et al. "Near Real-Time Monitoring of the Christmas 2018 Etna Eruption Using SEVIRI and Products Validation". Remote Sensing 12, n.º 8 (23 de abril de 2020): 1336. http://dx.doi.org/10.3390/rs12081336.
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On the morning of 24 December 2018, an eruptive event occurred at Etna, which was followed the next day by a strong sequence of shallow earthquakes. The eruptive episode lasted until 30 December, ranging from moderate strombolian to lava fountain activity coupled with vigorous ash/gas emissions and a lava flow effusion toward the eastern volcano flank of Valle del Bove. In this work, the data collected from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) instruments on board the Meteosat Second Generation (MSG) geostationary satellite are used to characterize the Etna activity by estimating the proximal and distal eruption parameters in near real time. The inversion of data indicates the onset of eruption on 24 December at 11:15 UTC, a maximum Time Average Discharge Rate (TADR) of 8.3 m3/s, a cumulative lava volume emitted of 0.5 Mm3, and a Volcanic Plume Top Height (VPTH) that reached a maximum altitude of 8 km above sea level (asl). The volcanic cloud ash and SO2 result totally collocated, with an ash amount generally lower than SO2 except on 24 December during the climax phase. A total amount of about 100 and 35 kt of SO2 and ash respectively was emitted during the entire eruptive period, while the SO2 fluxes reached peaks of more than 600 kg/s, with a mean value of about 185 kg/s. The SEVIRI VPTH, ash/SO2 masses, and flux time series have been compared with the results obtained from the ground-based visible (VIS) cameras and FLux Automatic MEasurements (FLAME) networks, and the satellite images collected by the MODerate resolution Imaging Spectroradiometer (MODIS) instruments on board the Terra and Aqua- polar satellites. The analysis indicates good agreement between SEVIRI, VIS camera, and MODIS retrievals with VPTH, ash, and SO2 estimations all within measurement errors. The SEVIRI and FLAME SO2 flux retrievals show significant discrepancies due to the presence of volcanic ash and a gap of data on the FLAME network. The results obtained in this study show the ability of geostationary satellite systems to characterize eruptive events from the source to the atmosphere in near real time during the day and night, thus offering a powerful tool to mitigate volcanic risk on both local population and airspace and to give insight on volcanic processes.
Tesis sobre el tema "Eruptive fluxes"
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Augustin, Thiebaut d'. "Les éléments halogènes dans les magmas, du traçage des conditions de stockage aux flux éruptifs". Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS370.
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Les éléments halogènes sont caractérisés par une configuration électronique S2P5 qui leur confère une très forte électronégativité leur permettant de former des ions halogénures très réactifs (X-, où X est un élément halogène). De par leur comportement volatil et incompatible dans la plupart des minéraux cristallisant dans les réservoirs magmatiques, leur concentration augmente dans la phase liquide résiduelle lors de la cristallisation fractionnée. Lorsque le magma remonte vers la surface, la solubilité des éléments volatils diminuant (parmi lesquels les éléments halogènes), ils s’exsolvent du magma sous forme de gaz. Les gaz émis lors des éruptions pliniennes sont propulsés à plusieurs kilomètres d’altitude et, selon l’importance de l’éruption, peuvent parvenir dans la stratosphère. Une fois injectés dans la stratosphère, les éléments halogènes ont un temps de résidence qui varie selon l’élément et le composé qu’il forme, et qui peut atteindre plusieurs années. Ils y déstabilisent les équilibres chimiques et provoquent la destruction de l’ozone stratosphérique. La méthode utilisée durant cette thèse consiste en une estimation du volume total d’un élément volatil donné émis lors d’une éruption, par la différence de concentration de l’élément dans le magma avant et après éruption. Le dégazage correspond à la différence de concentration de l’élément avant et après éruption. Cette méthode présente le double intérêt de permettre la mesure de la concentration totale de l’élément dans le magma, de manière non spécifique, et de ne pas requérir d’observation directe au moment de l’éruptionHalogen elements have a characteristic S2P5 electronic configuration which gives them a very high electronegativity. Hence, they form highly reactive halide ions (X-, where X is a halogen element). Because of their volatile and incompatible behaviour in most of the minerals crystallising in magma reservoirs, their concentration increases in the residual liquid phase during fractional crystallisation. As the magma rises to the surface, the solubility of the volatile elements (including the halogen elements) decreases and they exsolve from the magma as gases. The gases emitted during plinian eruptions are propelled several kilometres into the atmosphere and, depending on the size of the eruption, they may reach the stratosphere. Once the halogen elements injected into the stratosphere, their residence time depend on the element and the compound it forms, and can reach several years. The halogen elements destabilise chemical balances in the stratosphere and cause the destruction of stratospheric ozone. The method used in this thesis consists in an estimate of the total volume of a given volatile element that is emitted during an eruption, from the difference in concentration of the element in the magma before and after eruption. The degassing thus corresponds to the difference in concentration of the element before and after eruption. This method has the double advantage of allowing to measure the total concentration of the element in the magma, in a non-specific way, and of not requiring direct observation at the time of the eruption
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Yardley, S. L. "The role of flux cancellation in the formation of filaments and eruptive structures". Thesis, University College London (University of London), 2017. http://discovery.ucl.ac.uk/1539954/.
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The work conducted in this thesis represents a contribution towards understanding the important processes involved in the formation of filaments and eruptive structures in the solar atmosphere. In particular, the role that ongoing photospheric flux cancellation and associated magnetic reconnection plays in the origin of filament plasma. Also, to study how the magnetic field configuration evolves as flux cancellation proceeds to find indications of the onset of filament eruptions as coronal mass ejections (CMEs). This process is capable of re-configuring the supporting magnetic field from a sheared coronal arcade to a flux rope configuration, building up non-potential field in the atmosphere and storing free magnetic energy along the polarity inversion line. These helical configurations consist of concave-up sections or magnetic dips that provide locations for filament material to be supported against gravity. Flux cancellation observations, whereby small-scale opposite polarity features converge, collide and subsequently dis- appear in line-of-sight magnetic field can therefore, provide a way to investigate how much magnetic flux has been built into the magnetic field configuration that contains the filament before eruption. This process is crucial to the understanding of the onset of CMEs. In this thesis, a small sub-set of active regions have been studied. Observations of the photospheric field have been used to study the field evolution of active regions and its relationship to eruptions. To study the magnetic evolution of these regions an automated algorithm has been developed which tracks magnetic features in line-of-sight magnetic field data to calculate the total quantity and rate of flux cancellation. Chromospheric and coronal plasma observations have been used to study the presence of filament material and plasma flows, in relation to flux cancellation sites. Finally, these observations have been compared to the field configuration and locations of magnetic dips present in non-linear force-free field models.
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Gibb, Gordon P. S. "The formation and eruption of magnetic flux ropes in solar and stellar coronae". Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/7069.
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Flux ropes are magnetic structures commonly found in the solar corona. They are thought to play an important role in solar flares and coronal mass ejections. Understanding their formation and eruption is of paramount importance for our understanding of space weather. In this thesis the magnetofrictional method is applied to simulate the formation of flux ropes and track their evolution up to eruption both in solar and stellar coronae. Initially, the coronal magnetic field of a solar active region is simulated using observed magnetograms to drive the coronal evolution. From the sequence of magnetograms the formation of a flux rope is simulated, and compared with coronal observations. Secondly a procedure to produce proxy SOLIS synoptic magnetograms from SDO/HMI and SOHO/MDI magnetograms is presented. This procedure allows SOLIS-like synoptic magnetograms to be produced during times when SOLIS magnetograms are not available. Thirdly, a series of scaling laws for the formation and life-times of flux ropes in stellar coronae are determined as a function of stellar differential rotation and surface diffusion. These scaling laws can be used to infer the response of stellar coronae to the transport of magnetic fields at their surface. Finally, global long-term simulations of stellar corona are carried out to determine the coronal response to flux emergence and differential rotation. A bipole emergence model is developed and is used in conjunction with a surface flux transport model in order to drive the global coronal evolution. These global simulations allow the flux, energy and flux rope distributions to be studied as a function of a star's differential rotation and flux emergence rate.
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Gho, Inzunza Rayen Alina. "Determinación de parámetros eruptivos de flujos de lava del complejo volcánico Lonquimay (38°S), Andes del Sur". Tesis, Universidad de Chile, 2013. http://www.repositorio.uchile.cl/handle/2250/115551.
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GeólogaEl Complejo Volcánico Lonquimay (CVL) se encuentra en la Zona Volcánica Sur (38°). Ha estado activo principalmente durante el Holoceno, y ha generado productos esencialmente andesíticos. El CVL está compuesto por un estratovolcán principal, de un volumen cercano a los 20 km3, que se encuentra dividido en cinco unidades, donde las lavas más antiguas presentan longitudes de hasta 15 km, con morfologías de tipo aa, mientras que las coladas más jóvenes, tienen longitudes de hasta solo 3 km, y morfologías de tipo bloques. El Cordón Fisural Oriental (CFO, 10 km de largo), corresponde un sistema de fisuras ubicado en sector este del CVL, compuesto por numerosos conos piroclásticos en orientación NE. Las coladas del CFO presentan longitudes de hasta 10 km de largo, con morfologías de tipo bloques. En esta zona es donde han ocurrido las erupciones históricas del complejo. La petrografía de todas las unidades del CVL, se mantiene muy uniforme en el tiempo. Los parámetros eruptivos que controlaron la formación de estas coladas de lava no históricas fueron determinados gracias a un estudio detallado de sus morfologías, dimensiones y petrografía, obteniendo variaciones de estos valores en el tiempo a partir de mediciones y muestreos a diferentes distancias de la fuente de emisión. Esto se realizó con análisis dimensional de las coladas de lava, basado en un flujo de tipo Herschel-Bulkley, Los resultados obtenidos indican que las coladas de lava más antiguas del cono principal presentaron altas tasas eruptivas (hasta 433 m3 s-1), lo que junto al alto volumen emitido (~0,1 km3), permitieron la formación de largas coladas; estos valores habrían ido disminuyendo, a medida que se formó el estratovolcán, hasta el punto en que las últimas coladas solo alcanzan un par de kilómetros de largo, con tasas eruptivas del orden de 2 m3 s-1, y volúmenes de solo 0,01 km3. De acuerdo a las variaciones observadas, las dimensiones de las coladas estarían estrictamente ligadas a la tasa eruptiva y a los volúmenes emitidos. Estos parámetros estarían, a su vez, determinados por la presión que ejerce la masa de material acumulado sobre la cámara magmática, debido a la formación del estratovolcán: cuando mayor es el volumen del volcán, menores serán las tasas eruptivas y volúmenes generados. Por lo que luego de la superposición de las últimas unidades en el estratovolcán, los magmas habrían perdido la capacidad de ascender por el conducto principal, por lo que la actividad volcánica reciente se estaría llevando a cabo en el CFO, por las facilidades que presenta el sistema de fallas.
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MICHAUD, VALERIE. "L'enrichissement selectif en k, rb et cs des laves recentes de l'etna : role des fluides du systeme phreatique dans l'interaction magma encaissant sedimentaire et implications sur les dynamismes eruptifs". Paris 11, 1991. http://www.theses.fr/1991PA112182.
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L'evolution geochimique des laves historiques et recentes de l'etna, comparee a celle des laves anciennes nous a conduit a mettre en evidence une anomalie selective en k, rb et cs. L'objectif de ce travail de these a ete de determiner la signification petrogenetique de ce phenomenes, de son evolution soudaine et importante dans les laves recentes. L'etude systematique des caracteres volcanologiques et geochimiques de l'activite historique et recente montre que l'edifice volcanique a ete le siege d'une injection majeure (en volume) de magma basique au xviieme siecle. Les proprietes geochimiques de ce magma n'ont que tres peu change jusqu'a nos jours, a l'exception de l'anomalie selective en k, rb et cs qui devient perceptible et qui s'exprimera de maniere brusque et nette a partir de 1970-71. Depuis lors elle n'a cesse de croitre. L'anomalie en k, rb et cs est correlee a deux modifications majeures du fonctionnement du volcan: un accroissement de la frequence des eruptions (1 eruption par an depuis 1971) et une tres nette diminution des volumes de magma emis (inferieurs a 0,1 km#3). Apres avoir elimine plusieurs hypotheses, nous proposons d'expliquer cette evolution par des interactions superficielles entre le magma et les vastes surfaces d'echanges offertes par le systeme d'alimentation filonien. Certains flyschs du substratum sedimentaire representent des reservoirs contaminants potentiels, en raison de leur richesse en alcalins. Les etudes mineralogique et petrochimique detaillees des enclaves enallogenes, frequemment associees aux laves eruptees, ont permis de mettre en evidence certains mecanismes de contamination (metasomatose soustractive en elements alcalins (k, rb et cs) et deshydratation des materiaux sedimentaires au profit du magma). Nous suggerons que la contamination des magmas s'opere par transfert selectif du k, du rb et du cs sous l'effet d'une phase fluide provenant de l'encaissant sedimentaire. Les changements, intervenant au debut des annees 1970, ont reuni des conditions favorables a l'expression du processus de contamination. La proportion magma fluide contaminant en alcalins pourrait jouer un role determinant, non seulement dans l'expression de l'anomalie mais aussi dans l'evolution des dynamismes eruptifs, dont l'intensite n'a cesse de croitre
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Wilson, James Adams. "A New Volcanic Event Recurrence Rate Model and Code For Estimating Uncertainty in Recurrence Rate and Volume Flux Through Time With Selected Examples". Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6435.
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Recurrence rate is often used to describe volcanic activity. There are numerous documented ex- amples of non-constant recurrence rate (e.g. Dohrenwend et al., 1984; Condit and Connor, 1996; Cronin et al., 2001; Bebbington and Cronin, 2011; Bevilacqua, 2015), but current techniques for calculating recurrence rate are unable to fully account for temporal changes in recurrence rate. A local–window recurrence rate model, which allows for non-constant recurrence rate, is used to calculate recurrence rate from an age model consisting of estimated ages of volcanic eruption from a Monte Carlo simulation. The Monte Carlo age assignment algorithm utilizes paleomagnetic and stratigraphic information to mask invalid ages from the radiometric date, represented as a Gaussian probability density function. To verify the age assignment algorithm, data from Heizler et al. (1999) for Lathrop Wells is modeled and compared. Synthetic data were compared with expected results and published data were used for cross comparison and verification of recurrence rate and volume flux calculations. The latest recurrence rate fully constrained by the data is reported, based upon data provided in the referenced paper: Cima Volcanic Field, 33 +55/-14 Events per Ma (Dohren- wend et al., 1984), Cerro Negro Volcano, 0.29 Events per Year (Hill et al., 1998), Southern Nevada Volcanic Field, 4.45 +1.84/-0.87 (Connor and Hill, 1995) and Arsia Mons, Mars, 0.09 +0.14/-0.06 Events per Ma (Richardson et al., 2015). The local–window approach is useful for 1) identifying trends in recurrence rate and 2) providing the User the ability to choose the best median recurrence rate and 90% confidence interval with respect to temporal clustering.
Capítulos de libros sobre el tema "Eruptive fluxes"
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Gaizauskas, V. "On driving the eruption of a solar filament". En Physics of Magnetic Flux Ropes, 331–35. Washington, D. C.: American Geophysical Union, 1990. http://dx.doi.org/10.1029/gm058p0331.
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Olmos, Rodolfo, José Barrancos, Claudia Rivera, Francisco Barahona, Dina L. López, Benancio Henriquez, Agustín Hernández et al. "Anomalous Emissions of SO2 During the Recent Eruption of Santa Ana Volcano, El Salvador, Central America". En Terrestrial Fluids, Earthquakes and Volcanoes: The Hiroshi Wakita Volume II, 2489–506. Basel: Birkhäuser Basel, 2007. http://dx.doi.org/10.1007/978-3-7643-8720-4_8.
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Hernández, P. A., N. M. Pérez, J. C. Varekamp, B. Henriquez, A. Hernández, J. Barrancos, E. Padrón, D. Calvo y G. Melián. "Crater Lake Temperature Changes of the 2005 Eruption of Santa Ana Volcano, El Salvador, Central America". En Terrestrial Fluids, Earthquakes and Volcanoes: The Hiroshi Wakita Volume II, 2507–22. Basel: Birkhäuser Basel, 2007. http://dx.doi.org/10.1007/978-3-7643-8720-4_9.
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Kralj, Polona. "Submarine Stratovolcano Peperite Syn-Formational Alteration - A Case Study of the Oligocene Smrekovec Volcanic Complex, Slovenia". En Updates in Volcanology - Transdisciplinary Nature of Volcano Science. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95480.
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The Oligocene Smrekovec Volcanic Complex is a remnant of a submarine composite stratovolcano with a complex succession of lavas, autoclastic, pyroclastic, syn-eruptive resedimented volcaniclastic and siliciclastic deposits was a favourable environment for the development of peperites. Despite very complex alteration related to the stratovolcano-hosted hydrothermal system with a deep igneous source, locally elevated geothermal gradients and superimposed hydrothermal/geothermal regimes controlled by the emplacement of a shallow intrusive body, authigenic minerals in peperites - particularly pumpellyite and actinolite - show higher temperature stability ranges than those in the underlying and overlying volcanic deposits irrespectively of their lithofacies, porosity and permeability. The formation of authigenic minerals in peperites, such as laumontite, pumpellyite, epidote, prehnite or actinolite, was apparently controlled by ephemeral and localised high-temperature regimes originating from the parent lava flow. Heated pore waters in the host sediment that could have undergone local mixing with deuteric fluids circulated in peperites until thermal gradients persisted, and were the cause of alteration of juvenile clasts and the mingling sediment. The development of pumpellyite required a suitable precursor - fine-grained volcanic ash.
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Chelle-Michou, Cyril y Bertrand Rottier. "Transcrustal Magmatic Controls on the Size of Porphyry Cu Systems: State of Knowledge and Open Questions". En Tectonomagmatic Influences on Metallogeny and Hydrothermal Ore Deposits: A Tribute to Jeremy P. Richards (Volume I), 87–100. Society of Economic Geologists, 2021. http://dx.doi.org/10.5382/sp.24.06.
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Abstract Porphyry Cu deposits range over five orders of magnitude in size (<0.01 to >100 Mt of contained Cu) despite common and reproducible ore-forming processes across continents and geologic times. The formation and size of these deposits are thought to be controlled by the optimal alignment of commonplace geologic, physical, and chemical processes. However, the relative weight of such processes in modulating the size of porphyry Cu deposits remains poorly quantified. Over the last few decades, new geologic and experimental data, analytical developments, and improved numerical models of deep and upper-crustal magmatic reservoirs have provided new insights into the chemical and physical evolution of transcrustal magmatic systems that lead to the formation of porphyry Cu deposits. Available data show that porphyry Cu deposits are formed by large volumes of hydrothermal fluids outgassed from a cyclically rejuvenated upper-crustal magma reservoir composed of intermediate to felsic magmas derived from the differentiation of primitive arc basalts in the lower crust. This transcrustal view of the magmatic system implies that physical and chemical processes taking place during (1) the generation of intermediate to felsic magmas in the lower crust, (2) their subsequent ascent, followed by (3) cooling, crystallization, fluid exsolution, and outgassing in the upper crust can strongly influence the size of the resulting porphyry deposits. Here we show that most chemical factors that affect the fertility of magmatic systems are preset during magmatic differentiation in the deep crust. Importantly, these chemical processes are not specific to porphyry-forming magmas but are in fact characteristic of intermediate arc magmas in general. Within geologically permissible ranges, the chemical fertility of arc magmas can modulate the size of porphyry Cu deposits within one order of magnitude, insufficient to explain the full range of Cu endowment observed in these deposits. In contrast, physical aspects such as the lifetime (i.e., the combined duration of magma accumulation and crystallization) and volume of an effective magma body appear to be the major controls on the size of porphyry Cu deposits. The efficiency of the magmatic system refers to its ability to outgas fluids in a focused manner and yet avoid a catastrophic explosive volcanic eruption during incremental growth of the system through successive magma recharges. The intrusive magma flux, thermal gradient, and rheological state of the intruded crust all appear to be the major factors that influence the formation and size of the effective magma body, and thus, the formation and size of porphyry Cu deposits. We highlight the role of long-lived transcrustal arc maturation in developing this physical fertility and argue that the understanding of magmatic systems associated with porphyry deposits from a physical point of view will be the key to the definition of new exploration guidelines for giant porphyry Cu deposits.
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Overbay, William J., Tench C. Page, Dennis J. Krasowski, Mark H. Bailey y Thomas C. Matthews. "Geology, Structural Setting, and Mineralization of the Dolores District, Chihuahua, Mexico". En Northern Sierra Madre Occidental Gold-Silver Mines, Mexico, 29–43. Society of Economic Geologists, 2010. http://dx.doi.org/10.5382/gb.42.ch03.
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Abstract The Dolores project is located in the Sierra Madre Occidental mountain range of northern Mexico, near the historic mining district of Dolores in the state of Chihuahua. Exploratory drilling by Minefinders Corporation, Ltd., began in 1996 and has resulted in the discovery of one of Mexico's largest undeveloped gold-silver deposits. The regional geologic history of the area is dominated by three phases of volcanism: (1) A period of intermediate composition volcanism that resulted in deposition of voluminous andesitic flows and volcaniclastics interlayered with lesser amounts of felsic ash (the Lower volcanic series). This occurred from ˜46 to 35 Ma, (2) The first phase was closely followed by eruption of dominantly felsic ash flow tuffs and flows of rhyolitic to latitic composition (the Upper volcanic series), which occurred between ˜35 and 27 Ma, (3) Finally, intermittent eruption of basaltic andesite in thin flows occurred from <27 to 3 Ma. Deposition of the Baucarit Formation, a conglomeratic basin-fill sedimentary unit with thin interlayers of basalt, also occurred in down-dropped basins during the Pliocene to Pleistocene, or approximately 5 to 1 m.y. ago. Definitive age dates for the mineralization at Dolores have yet to be established. Ages of vein-style Ag-Au mineralization throughout the Sierra Madre Occidental are reported to be between about 49 to 27 Ma (Clark et al., 1979). Geologic observations at Dolores suggest that mineralization occurred following the episode of voluminous andesitic volcanism and generally at the same time as deposition of the overlying latitic pyroclastic tuffs of the Lower volcanic series, because mineralization and alteration are generally confined to the andesites and the lowermost portion of the volcaniclastic rocks. It follows that the Dolores mineralization occurred prior to deposition of the Upper volcanic series and dates from about 38 to 35 Ma of age. Within the district, regional north-northwest-trending structures controlled emplacement of a series of porphyritic andesitic to latitic dikes and sills in conjunction with emplacement of several larger hypabyssal north-northwest-elongate, domal intrusive bodies that formed during deposition of the Lower volcanic series. Epithermal, low-sulfidation fluids, believed to be associated with the waning stages of the intrusive episode, deposited quartz-adularia and precious metals. Wider zones of mineralization formed within areas of higher permeability and where boiling and episodic hydrothermal brecciation were focused in areas of greater structural complexity. Consequently, the mineralization occurs both within high-level stockworks, breccias, and disseminations formed near the contact of the felsic volcaniclastic rocks with the underlying andesites and within more tightly confined north-northwest-trending feeders that continue to depth. Gold predominates in the higher levels of the system and can be found across widths of 100 m or more at an average grade of from 1 to up to 2 g/t. Mineralized feeders occur below these zones and can be from 2 to more than 20 m in width, with gold content of up to 10 to more than 200 g/t and silver content of 1 to more than 5 kg/t. In the studied resource area, Ag/Au ratios appear to be zoned about a central domal intrusive and vary from about 100:1 near the intrusive to less than 10:1 to the north and south. Trace element geochemistry includes variable Hg, As, and Sb in the higher elevations with increasing amounts of Pb, Zn, and minor Cu at depth. A combined program of reverse circulation and core drilling totaling 61,441 m in 291 holes has revealed mineralization that occurs within an area that is approximately 2,800 m long by more than 600 m across. Additional drill intercepts and surface geochemical assays outside of this area indicate the potential to increase the resource base throughout an overall area that is approximately 4,000 m by 1,200 m. A resource study within the most densely drilled 1,900 by 300 m area was completed in 2000. Economic analysis, based on work by a major international engineering firm, indicates that a bulk-minable resource of approximately 67 Mt, at a gold equivalent (Aueq) grade of 1.85 g/t, can be developed by open-pit mining methods. The total calculated resource within the study area is 100.1 Mt containing 2.45 Moz of gold and 129.7 Moz of silver, or 4.62 Moz of Aueq at a 60:1 ratio.
Actas de conferencias sobre el tema "Eruptive fluxes"
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Fendley, Isabel, Tushar Mittal, Courtney J. Sprain, Mark Marvin-DiPasquale, Nicole Mizrahi, Paul R. Renne, Stephen Self, Thomas S. Tobin y Lucas N. Weaver. "QUANTITATIVE ESTIMATES OF DECCAN FLOOD BASALT ERUPTIVE FLUXES AND CLIMATE CONSEQUENCES". En GSA Annual Meeting in Phoenix, Arizona, USA - 2019. Geological Society of America, 2019. http://dx.doi.org/10.1130/abs/2019am-338145.
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Jeong, Dong Woon, Kwang Uoong Koh y Sang Yong Lee. "Preliminary Consideration to Avoid Eruptive Flow Boiling in Microchannels". En ASME 2003 1st International Conference on Microchannels and Minichannels. ASMEDC, 2003. http://dx.doi.org/10.1115/icmm2003-1076.
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With boiling flows in very smooth heated channels, in general, the bulk liquid is superheated before the bubble formation takes place at the wall surface. Thus the eruptive boiling occurs once the superheat requirement for nucleation is satisfied, and this can be a source of flow instability. In the present work, a preliminary consideration has been given to predict the limiting heat flux for stable boiling in microchannels. The minimum heat-flux value to avoid this eruptive boiling is inversely proportional to the square of the channel diameter, and becomes enormously large as the channel diameter decreases. The stable heat-flux limit also depends on the cavity size in the channel wall. A map showing stable nucleation criteria was given and discussions were made on the simplifying assumptions made for the analysis.
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Haendler, Brenda E., Dorian Liepmann y Albert P. Pisano. "The Dynamic Pressure Response of Phase Eruption in Micro Channels". En ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56595.
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New results are presented in this paper quantifying the dynamic pressure response that is produced as a result of the phase eruption phenomenon in micro channels at a flow rate of 0.5 ml/min. The experimentally measured time-varying pressure change from phase eruption is profiled for water and conclusions are drawn which will help guide the design and operation of an intake manifold for a micro engine. Employing the method of discrete Fourier transform, the amplitude and frequency of the pressure response is characterized for a variety of flow conditions detailing the sensitivity of the system to external changes. Relationships are established between the temperature and Reynolds number of the flow and the pressure in the channel for non-boiling flows. The governing equations for flow in micro channels are presented and conclusions on modeling phase change are discussed. The single-phase relationships discussed are deviated from once phase eruption begins and future modeling directions are proposed.
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Torabi, Mohsen, Ahmed A. Hemeda, Anupam Mishra, Ting Liu y Yanbao Ma. "LIQUID BRIDGE ERUPTION FOR MESOSCALE GRAVURE PRINTING USING MULTI-BODY DISSIPATIVE PARTICLE DYNAMICS". En 4th Thermal and Fluids Engineering Conference. Connecticut: Begellhouse, 2019. http://dx.doi.org/10.1615/tfec2019.nmf.028350.
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Saito, T., H. Yamashita y K. Takayama. "CFD Application to Construction of Hazard Maps of Volcanic Eruptions". En ASME 2002 Pressure Vessels and Piping Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/pvp2002-1599.
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Shock wave propagation due to explosive-type volcano eruptions are numerically simulated in order to produce hazard maps. Different types of damages caused by pyroclastic-surge and ballistic fragments as well as positive and negative pressure loading are related to the maximum overpressure of the blast waves. Hazard maps produced by the present method is useful for establishing better safety countermeasures for volcanic eruptions. Simulations of blast wave propagation take the complex terrain of the interested area into account. Several eruption models for the energy release such as the reservoir-break model and the jet models are considered and discussed. The three-dimensional numerical code employs the finite volume method with WAF scheme for evaluating the numerical fluxes at the cell interface. The WAF scheme is one of the high-order Godunov schemes and HLLC approximate Riemann solution is used in the present work.
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Wood, B. E., M. Karovska, J. Chen, G. E. Brueckner, J. W. Cook y R. A. Howard. "Comparing the kinematic properties of CMEs observed by LASCO and EIT with models of erupting flux ropes". En The solar wind nine conference. AIP, 1999. http://dx.doi.org/10.1063/1.58708.
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Sakurai, Hisashi, Yasuo Koizumi y Hiroyasu Ohtake. "Critical Heat Flux by High Velocity Liquid Flow in Narrow Rectangular Channel". En ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-67945.
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Experiments of critical heat flux of extremely thin-fast plate jet film sub-cooled flow were conducted. The extremely thin-fast film-type jet of sub-cooled water was erupted into a stagnant pool. The heat transfer is augmented by the fast jet flow on the heat transfer surface. Vapor generated on the surface is easily taken away from the surface by the fast jet flow and leaves upward from the surface. The static head of water in the pool depress down the fast film-type jet flow on to the heat transfer surface and may collapse the vapor film that is formed between the heat transfer surface and the fast film flow. All these combine to have the possibility to improve the critical heat flux. In the experiments, the liquid sub-cooling was in the range of 30 ∼ 70 K. The thickness of the jet film was 0.2 mm and 0.5 mm. The width of the jet film was 2 mm. The velocity of the erupting jet film was 5.0 ∼ 32 m/s. The heat transfer surface was 2.0 × 2.0 mm heated electrically. The heat transfer surface was placed on the bottom of the pool. The fast-thin film jet was erupted on the bottom of the pool parallel to the heat transfer surface. Bubble behavior generated on the heat transfer surface was recorded by a high speed video camera at 10,000 frames/s. The highest critical heat flux obtained up to now is 3.2 × 107 W/m2. The analytical model of the critical heat flux for the present flow system will be presented.