Journal articles: 'Planetary ions'

1

Dean Pesnell, W., and J. M. Grebowsky. "Meteoric ions in planetary ionospheres." Advances in Space Research 27, no. 11 (January 2001): 1807–14. http://dx.doi.org/10.1016/s0273-1177(01)00264-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Kallio, Esa. "Escaping of planetary ions from Mars and Venus." Advances in Space Research 27, no. 11 (January 2001): 1815–24. http://dx.doi.org/10.1016/s0273-1177(01)00330-1.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Strazzulla, G., J. R. Brucato, G. Cimino, G. Leto, and F. Spinella. "Interaction of solar wind ions with planetary surfaces." Advances in Space Research 15, no. 10 (January 1995): 13–17. http://dx.doi.org/10.1016/0273-1177(94)00145-q.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Lilensten, J., C. Simon Wedlund, M. Barthélémy, R. Thissen, D. Ehrenreich, G. Gronoff, and O. Witasse. "Dications and thermal ions in planetary atmospheric escape." Icarus 222, no. 1 (January 2013): 169–87. http://dx.doi.org/10.1016/j.icarus.2012.09.034.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Ibadov, Subhon. "On the production of multicharge ions in planetary nebulae." Proceedings of the International Astronomical Union 7, S283 (July 2011): 392–93. http://dx.doi.org/10.1017/s1743921312011581.

Full text

Abstract:

AbstractProduction of multicharge ions due to generation of hot expanding plasma blobs, short-living “compound particles”, at high-velocity collisions between dust grains of a planetary nebula and dust particles of the interstellar medium is analytically considered. Dependence of the multiplicity of charge of produced ions on the relative velocity of colliding dust particles is determined.

APA, Harvard, Vancouver, ISO, and other styles

6

Nahar, Sultana N. "Atomic Processes in Planetary Nebulae." Symposium - International Astronomical Union 209 (2003): 325–34. http://dx.doi.org/10.1017/s0074180900208942.

Full text

Abstract:

A hot central star illuminating the surrounding ionized H II region usually produces very rich atomic spectra resulting from basic atomic processes: photoionization, electron-ion recombination, bound-bound radiative transitions, and collisional excitation of ions. Precise diagnostics of nebular spectra depend on accurate atomic parameters for these processes. Latest developments in theoretical computations are described, especially under two international collaborations known as the Opacity Project (OP) and the Iron Project (IP), that have yielded accurate and large-scale data for photoionization cross sections, transition probabilities, and collision strengths for electron impact excitation of most astrophysically abundant ions. As an extension of the two projects, a self-consistent and unified theoretical treatment of photoionization and electron-ion recombination has been developed where both the radiative and the dielectronic recombination processes are considered in an unified manner. Results from the Ohio State atomic-astrophysics group, and from the OP and IP collaborations, are presented. A description of the electronic web-interactive database, TIPTOPBASE, with the OP and the IP data, and a compilation of recommended data for effective collision strengths, is given.

APA, Harvard, Vancouver, ISO, and other styles

7

Liu, Xiaowei. "Atomic processes in planetary nebulae." Proceedings of the International Astronomical Union 7, S283 (July 2011): 131–38. http://dx.doi.org/10.1017/s1743921312010836.

Full text

Abstract:

AbstractProgress in the study of the atomic processes in planetary nebulae (PNe) is reviewed, focusing on the literature published since the last IAU symposium on PNe five years ago. High quality photoionization cross sections and recombination coefficients are now available for the first six ions of the trans-iron elements selenium and krypton, enabling robust modeling of their ionization structure and consequently converting the measured ionic abundances to elemental abundances. Major progress has been achieved in utilizing the recombination spectra of helium and heavy element ions to probe the nebular physical conditions. New ab initio, density-dependent effective recombination coefficients have been calculated for the recombination spectra of O ii and N ii, down to very low temperatures (~ 100–300 K). Plasma diagnostics based entirely on those heavy element recombination lines are developed and applied to the observations. It is shown that these heavy element recombination lines originate predominately from cold plasmas of temperatures ~ 1,000 K, in agreement with the predictions of the bi-abundance model that has been proposed to explain the dichotomy of nebular plasma diagnostics and abundance determinations using collisional excited lines (CELs) on the one hand and optical recombination lines (ORLs) on the other.

APA, Harvard, Vancouver, ISO, and other styles

8

Delcourt, D. C. "On the supply of heavy planetary material to the magnetotail of Mercury." Annales Geophysicae 31, no. 10 (October 8, 2013): 1673–79. http://dx.doi.org/10.5194/angeo-31-1673-2013.

Full text

Abstract:

Abstract. We examine the transport of low-energy heavy ions of planetary origin (O+, Na+, Ca+) in the magnetosphere of Mercury. We show that, in contrast to Earth, these ions are abruptly energized after ejection into the magnetosphere due to enhanced curvature-related parallel acceleration. Regardless of their mass-to-charge ratio, the parallel speed of these ions is rapidly raised up to ~ 2 VE × B (denoting by VE × B the magnitude of the local E × B drift speed), in a like manner to Fermi-type acceleration by a moving magnetic mirror. This parallel energization is such that ions with very low initial energies (a few tenths of eVs) can overcome gravity and, regardless of species or convection rate, are transported over comparable distances into the nightside magnetosphere. The region of space where these ions reach the magnetotail is found to extend over altitudes similar to those where enhanced densities are noticeable in the MESSENGER data, viz., from ~ 1000 km up to ~ 6000 km in the pre-midnight sector. The observed density enhancements may thus follow from E × B related focusing of planetary material of dayside origin into the magnetotail. Due to the planetary magnetic field offset, an asymmetry is found between drift paths anchored in the Northern and Southern hemispheres, which puts forward a predominant role of heavy material originating in the Northern Hemisphere in populating the innermost region of Mercury's magnetotail.

APA, Harvard, Vancouver, ISO, and other styles

9

Thissen, Roland, Olivier Witasse, Odile Dutuit, Cyril Simon Wedlund, Guillaume Gronoff, and Jean Lilensten. "Doubly-charged ions in the planetary ionospheres: a review." Physical Chemistry Chemical Physics 13, no. 41 (2011): 18264. http://dx.doi.org/10.1039/c1cp21957j.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Jarvinen, R., and E. Kallio. "Energization of planetary pickup ions in the solar system." Journal of Geophysical Research: Planets 119, no. 1 (January 2014): 219–36. http://dx.doi.org/10.1002/2013je004534.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Sterling, N. C., H. L. Dinerstein, S. Hwang, S. Redfield, A. Aguilar, M. C. Witthoeft, D. Esteves, et al. "Improved Neutron-Capture Element Abundances in Planetary Nebulae." Publications of the Astronomical Society of Australia 26, no. 3 (2009): 339–44. http://dx.doi.org/10.1071/as08067.

Full text

Abstract:

AbstractSpectroscopy of planetary nebulae (PNe) provides the means to investigate s-process enrichments of neutron(n)-capture elements that cannot be detected in Asymptotic Giant Branch (AGB) stars. However, accurate abundance determinations of these elements present a challenge. Corrections for unobserved ions can be large and uncertain, since in many PNe only one ion of a given n-capture element has been detected. Furthermore, the atomic data governing the ionization balance of these species are not well-determined, inhibiting the derivation of accurate ionization corrections. We present initial results of a program that addresses these challenges. Deep high-resolution optical spectroscopy of ∼20 PNe has been performed to detect emission lines from trans-iron species including Se, Br, Kr, Rb and Xe. The optical spectral region provides access to multiple ions of these elements, which reduces the magnitude and importance of uncertainties in the ionization corrections. In addition, experimental and theoretical efforts are providing determinations of the photoionization cross sections and recombination rate coefficients of Se, Kr and Xe ions. These new atomic data will make it possible to derive robust ionization corrections for these elements. Together, our observational and atomic data results will enable n-capture element abundances to be determined with unprecedented accuracy in ionized nebulae.

APA, Harvard, Vancouver, ISO, and other styles

12

Vaisberg, O. L., A. V. Leibov, V. N. Smirnov, L. A. Avanov, J. J. Bertelier, K. Torcar, F. Leblan, et al. "Imaging mass-spectrometer of ions for studying near-planetary plasma." Cosmic Research 44, no. 3 (May 2006): 202–8. http://dx.doi.org/10.1134/s001095250603004x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Schlachter, A. S. "Seeing Inside a Hot Plasma: Photoionization of Ions." Solid State Phenomena 107 (October 2005): 69–74. http://dx.doi.org/10.4028/www.scientific.net/ssp.107.69.

Full text

Abstract:

Photoionization of ions is an important atomic process in very hot extended plasmas, for example, in objects of astrophysical interest. Planetary nebulae as a stage in the evolution of stars are one significant example. Modeling of their formation and composition requires detailed information about atomic processes in a very highly ionized plasma, including cross sections for photoionization of ions.

APA, Harvard, Vancouver, ISO, and other styles

14

Salas, J. Bernard, S. R. Pottasch, P. R. Wesselius, and P. Marigo. "Accurate Abundances Determination of Planetary Nebulae." Symposium - International Astronomical Union 209 (2003): 376. http://dx.doi.org/10.1017/s0074180900209078.

Full text

Abstract:

Accurate chemical abundances for the following planetary nebulae (PNe); NGC 6537, He 2-111, NGC 6302, NGC 6445, NGC 6741, NGC 7027, NGC 7662, NGC 2440 and NGC 5315 have been derived using data from the Infrared Space Observatory (ISO) and the International Ultraviolet Explorer (IUE). Optical data from the literature has also been used. These work has been published by Pottasch et al. (2001), Bernard Salas et al. (2001 and 2002). In particular, the use of the ISO data has reduced the need for ionization correction factors. Furthermore, infrared data avoid or reduce many problems when deriving these abundances, namely: temperature fluctuations in the nebula, and extinction corrections. The electron temperature (Te) and density of the PNe has been derived. For those PNe in which the Te has been derived for several ions a trend with the ionization potential is present. Ions with high stages of ionization give higher Te, probably because they are formed close to the central star. The chemical abundances measured in these PNe give some hint of the nucleosynthesis and mixing processes experienced by their progenitor stars. In this view, a preliminary comparison with synthetic TP-AGB models is made (Bernard Salas et al. (in prep.)). NGC 7027, NGC 6741, NGC 2440, and NGC 6445 are consistent with the occurrence of the 3rd dredge-up due to both C12 and He4 enrichment. NGC 6537, NGC 6302, and He 2-111 are likely to have stellar progenitors experiencing hot bottom burning due to the low C12 and high N14 abundances.

APA, Harvard, Vancouver, ISO, and other styles

15

Jarvinen, R., E. Kallio, P. Janhunen, S. Barabash, T. L. Zhang, V. Pohjola, and I. Sillanpää. "Oxygen ion escape from Venus in a global hybrid simulation: role of the ionospheric O<sup>+</sup> ions." Annales Geophysicae 27, no. 11 (November 27, 2009): 4333–48. http://dx.doi.org/10.5194/angeo-27-4333-2009.

Full text

Abstract:

Abstract. We study the solar wind induced oxygen ion escape from Venus' upper atmosphere and the Venus Express observations of the Venus-solar wind interaction by the HYB-Venus hybrid simulation code. We compare the simulation to the magnetic field and ion observations during an orbit of nominal upstream conditions. Further, we study the response of the induced magnetosphere to the emission of planetary ions. The hybrid simulation is found to be able to reproduce the main observed regions of the Venusian plasma environment: the bow shock (both perpendicular and parallel regions), the magnetic barrier, the central tail current sheet, the magnetic tail lobes, the magnetosheath and the planetary wake. The simulation is found to best fit the observations when the planetary \\oxy~escape rate is in the range from 3×1024 s−1 to 1.5×1025 s−1. This range was also found to be a limit for a test particle-like behaviour of the planetary ions: the higher escape rates manifest themselves in a different global configuration of the Venusian induced magnetosphere.

APA, Harvard, Vancouver, ISO, and other styles

16

Pottasch, S. R., D. A. Beintema, J. Bernard Salas, and W. A. Feibelman. "Abundances in Planetary Nebulae: Including ISO Results." Symposium - International Astronomical Union 209 (2003): 353–60. http://dx.doi.org/10.1017/s0074180900209005.

Full text

Abstract:

The far infrared nebular spectrum provides a valuable complement to the observed lines in other spectral regions. There are several reasons for this, the most important being the large increase in the number of ions observed, and the fact that the abundances found from these lines are relatively insensitive to the electron temperature. This leads to a more accurate determination of the abundances. To date, twelve PN have had abundances determined in this way. These results are summarized. The evolution of the central star is discussed in the light of these results.

APA, Harvard, Vancouver, ISO, and other styles

17

Zurbuchen, T. H., J. M. Raines, J. A. Slavin, D. J. Gershman, J. A. Gilbert, G. Gloeckler, B. J. Anderson, et al. "MESSENGER Observations of the Spatial Distribution of Planetary Ions Near Mercury." Science 333, no. 6051 (September 29, 2011): 1862–65. http://dx.doi.org/10.1126/science.1211302.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Schöning, T., and K. Butler. "Electron excitation of heavy elements in Planetary Nebulae." Symposium - International Astronomical Union 180 (1997): 279. http://dx.doi.org/10.1017/s0074180900130979.

Full text

Abstract:

Modern observational equipment makes it possible to identify extremely weak metal lines in deep surveys of the optical and near-IR region of the electromagnetic spectrum. In particular, collisionally excited lines from heavy ions (Z > 30) have been recently identified in the spectrum of NGC 7027 (Péquignot & Baluteau 1994). However, detailed quantitative analyses of the observed lines have not been feasible due to the lack of accurate collisional data for the heavy elements.

APA, Harvard, Vancouver, ISO, and other styles

19

Delcourt, D. C., S. Grimald, F. Leblanc, J. J. Berthelier, A. Millilo, A. Mura, S. Orsini, and T. E. Moore. "A quantitative model of the planetary Na<sup>+</sup> contribution to Mercury’s magnetosphere." Annales Geophysicae 21, no. 8 (August 31, 2003): 1723–36. http://dx.doi.org/10.5194/angeo-21-1723-2003.

Full text

Abstract:

Abstract. We examine the circulation of heavy ions of planetary origin within Mercury’s magnetosphere. Using single particle trajectory calculations, we focus on the dynamics of sodium ions, one of the main species that are ejected from the planet’s surface. The numerical simulations reveal a significant population in the near-Mercury environment in the nightside sector, with energetic (several keV) Na + densities that reach several tenths cm-3 at planetary perihelion. At aphelion, a lesser (by about one order of magnitude) density contribution is obtained, due to weaker photon flux and solar wind flux. The numerical simulations also display several features of interest that follow from the small spatial scales of Mercury’s magnetosphere. First, in contrast to the situation prevailing at Earth, ions in the magnetospheric lobes are found to be relatively energetic (a few hundreds of eV), despite the low-energy character of the exospheric source. This results from enhanced centrifugal acceleration during E × B transport over the polar cap. Second, the large Larmor radii in the mid-tail result in the loss of most Na + into the dusk flank at radial distances greater than a few planetary radii. Because gyroradii are comparable to, or larger than, the magnetic field variation length scale, the Na + motion is also found to be non-adiabatic throughout most of Mercury’s equatorial magnetosphere, leading to chaotic scattering into the loss cone or meandering (Speiser-type) motion in the near-tail. As a direct consequence, a localized region of energetic Na + precipitation develops at the planet’s surface. In this region which extends over a wide range of longitudes at mid-latitudes ( ~ 30°–40°), one may expect additional sputtering of planetary material.Key words. Magnetospheric physics (planetary magnetospheres) – Space plasma physics (charged particle motion and acceleration; numerical simulation studies)

APA, Harvard, Vancouver, ISO, and other styles

20

Nikitin, A. A., A. F. Kholtygin, A. A. Sapar, and T. H. Feklistova. "Abundances of C, N and O in Planetary Nebulae." Symposium - International Astronomical Union 131 (1989): 218. http://dx.doi.org/10.1017/s0074180900138306.

Full text

Abstract:

The abundances of C, N and O in planetary nebulae must correspond to the evolutionary status of their progenitor red giant stars. The best spectral features for abundance determination of these elements are the recombination lines, which depend weakly on the variations of Te and ne. The abundance ratio of the ions A+ and H+ can be given by [1–3].

APA, Harvard, Vancouver, ISO, and other styles

21

Delcourt, D. C., T. E. Moore, and M. C. H. Fok. "Ion dynamics during compression of Mercury's magnetosphere." Annales Geophysicae 28, no. 8 (August 3, 2010): 1467–74. http://dx.doi.org/10.5194/angeo-28-1467-2010.

Full text

Abstract:

Abstract. Because of the small planetary magnetic field as well as proximity to the Sun that leads to enhanced solar wind pressure as compared to Earth, the magnetosphere of Mercury is very dynamical and at times subjected to prominent compression. We investigate the dynamics of magnetospheric ions during such compression events. Using three-dimensional single-particle simulations, we show that the electric field induced by the time varying magnetic field can lead to significant ion energization, up to several hundreds of eVs or a few keVs. This energization occurs in a nonadiabatic manner, being characterized by large enhancements of the ion magnetic moment and bunching in gyration phase. It is obtained when the ion cyclotron period is comparable to the field variation time scale. This condition for nonadiabatic heating is realized in distinct regions of space for ions with different mass-to-charge ratios. During compression of Mercury's magnetosphere, heavy ions originating from the planetary exosphere may be subjected to such an abrupt energization, leading to loading of the magnetospheric lobes with energetic material.

APA, Harvard, Vancouver, ISO, and other styles

22

Jarvinen, R., D. A. Brain, and J. G. Luhmann. "Dynamics of planetary ions in the induced magnetospheres of Venus and Mars." Planetary and Space Science 127 (August 2016): 1–14. http://dx.doi.org/10.1016/j.pss.2015.08.012.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Verigin, M. I., N. M. Shutte, A. A. Galeev, K. I. Gringauz, G. A. Kotova, A. P. Remizov, H. Rosenbauer, et al. "Ions of planetary origin in the Martian magnetosphere (Phobos 2/TAUS experiment)." Planetary and Space Science 39, no. 1-2 (January 1991): 131–37. http://dx.doi.org/10.1016/0032-0633(91)90135-w.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Badman, S. V., and S. W. H. Cowley. "Significance of Dungey-cycle flows in Jupiter's and Saturn's magnetospheres, and their identification on closed equatorial field lines." Annales Geophysicae 25, no. 4 (May 8, 2007): 941–51. http://dx.doi.org/10.5194/angeo-25-941-2007.

Full text

Abstract:

Abstract. We consider the contribution of the solar wind-driven Dungey-cycle to flux transport in Jupiter's and Saturn's magnetospheres, the associated voltages being based on estimates of the magnetopause reconnection rates recently derived from observations of the interplanetary medium in the vicinity of the corresponding planetary orbits. At Jupiter, the reconnection voltages are estimated to be ~150 kV during several-day weak-field rarefaction regions, increasing to ~1 MV during few-day strong-field compression regions. The corresponding values at Saturn are ~25 kV for rarefaction regions, increasing to ~150 kV for compressions. These values are compared with the voltages associated with the flows driven by planetary rotation. Estimates of the rotational flux transport in the "middle" and "outer" magnetosphere regions are shown to yield voltages of several MV and several hundred kV at Jupiter and Saturn respectively, thus being of the same order as the estimated peak Dungey-cycle voltages. We conclude that under such circumstances the Dungey-cycle "return" flow will make a significant contribution to the flux transport in the outer magnetospheric regions. The "return" Dungey-cycle flows are then expected to form layers which are a few planetary radii wide inside the dawn and morning magnetopause. In the absence of significant cross-field plasma diffusion, these layers will be characterized by the presence of hot light ions originating from either the planetary ionosphere or the solar wind, while the inner layers associated with the Vasyliunas-cycle and middle magnetosphere transport will be dominated by hot heavy ions originating from internal moon/ring plasma sources. The temperature of these ions is estimated to be of the order of a few keV at Saturn and a few tens of keV at Jupiter, in both layers.

APA, Harvard, Vancouver, ISO, and other styles

25

Delcourt, D. C., T. E. Moore, and M. C. H. Fok. "On the effect of IMF turning on ion dynamics at Mercury." Annales Geophysicae 29, no. 6 (June 10, 2011): 987–96. http://dx.doi.org/10.5194/angeo-29-987-2011.

Full text

Abstract:

Abstract. We investigate the effect of a rotation of the Interplanetary Magnetic Field (IMF) on the transport of magnetospheric ion populations at Mercury. We focus on ions of planetary origin and investigate their large-scale circulation using three-dimensional single-particle simulations. We show that a nonzero BX component of the IMF leads to a pronounced asymmetry in the overall circulation pattern. In particular, we demonstrate that the centrifugal acceleration due to curvature of the E × B drift paths is more pronounced in one hemisphere than the other, leading to filling of the magnetospheric lobes and plasma sheet with more or less energetic material depending upon the hemisphere of origin. Using a time-varying electric and magnetic field model, we investigate the response of ions to rapid (a few tens of seconds) re-orientation of the IMF. We show that, for ions with gyroperiods comparable to the field variation time scale, the inductive electric field should lead to significant nonadiabatic energization, up to several hundreds of eVs or a few keVs. It thus appears that IMF turning at Mercury should lead to localized loading of the magnetosphere with energetic material of planetary origin (e.g., Na+).

APA, Harvard, Vancouver, ISO, and other styles

26

Borisov, N., and M. Fränz. "Excitation of low frequency oscillations in a planetary magnetosheath by supersonic shear flow." Nonlinear Processes in Geophysics 18, no. 2 (March 21, 2011): 209–21. http://dx.doi.org/10.5194/npg-18-209-2011.

Full text

Abstract:

Abstract. We show that the slow magnetosonic (SM) perturbations generated in the vicinity of the magnetopause, due to the excitation of the Kelvin-Helmholtz (K.-H.) instability in the case of a supersonic flow velocity, are transformed into fast magnetosonic (FM) waves which can propagate into the magnetosheath. Under the conditions discussed in this paper, the FM wave has negative energy in the stationary (magnetospheric) coordinate frame. Due to this the outgoing FM wave increases the growth rate of the K.-H. instability excited at the magnetopause. Within the linear theory, we investigate the influence of the excited FM wave on the growth rate of the K.-H. instability. Simultaneously we predict the transformation of the SM mode into kinetic Alfvén (KA) mode. Thus, in general, two types of waves with different polarizations (the KA wave and the FM wave) should appear in the magnetosheath due to the excitation of the K.-H. instability. At the same time, the SM perturbations are only present in the localized region where the K.-H. instability is excited. To correctly describe the excitation of waves, we use two-fluid (for electrons and ions) magnetohydrodynamics. This approach is more general than the ideal magnetohydrodynamics and allows us to take into account the effects associated with the finite Larmor radius of ions. Also it can be used to investigate the K.-H. instability in a multi-component plasma, or in the case where the frequency of perturbations is of the order of the gyrofrequency of oxygen ions which may occur, for example, at the magnetosheath of Mars.

APA, Harvard, Vancouver, ISO, and other styles

27

HACKENBERG, PETER, GOTTFRIED MANN, and ECKART MARSCH. "Solitons in multi-ion plasmas." Journal of Plasma Physics 60, no. 4 (November 1998): 845–59. http://dx.doi.org/10.1017/s0022377898007193.

Full text

Abstract:

In the heliosphere large fluctuations of the magnetic field are sometimes observed, especially at shocks (e.g. travelling interplanetary shocks, planetary bow waves, and shocks related to corotating interaction regions). The large fluctuations very often have an amplitude that reaches easily four or five times the magnitude of the quiet magnetic field. Since the plasma mostly contains a non-negligible fraction of heavy ions (e.g. helium ions or cometary water ions), these magnetic field fluctuations are described in terms of three-fluid equations. Here electrons, protons and heavy ions are considered as separate fluids interacting with themselves by electromagnetic forces. The three-fluid equations are treated in such a way that we are searching for one-dimensional stationary waves. Thus the equations are reduced to a fully nonlinear set of ordinary differential equations, which have been evaluated numerically with respect to solitary waves. Subsequently, examples of solitary waves in a electron- proton plasma loaded with 10 % 4He2+ ions are presented. For instance, an enrichment of helium ions is observed within the solitary waves.

APA, Harvard, Vancouver, ISO, and other styles

28

Chernogor, Alexey, Igor Blinkov, and Alexey Volkhonskiy. "Monte Carlo calculation of the energy parameters and spatial distribution of the cathodic arc ions while passing through the macro-particles filters." International Journal of Computational Physics Series 1, no. 1 (February 27, 2018): 30–34. http://dx.doi.org/10.29167/a1i1p30-34.

Full text

Abstract:

The flow, energy distribution and concentrations profiles of Ti ions in cathodic arc are studied by test particle Monte Carlo simulations with considering the mass transfer through the macro-particles filters with inhomogeneous magnetic field. The loss of ions due to their deposition on filter walls was calculated as a function of electric current and number of turns in the coil. The magnetic field concentrator that arises in the bending region of the filters leads to increase the loss of the ions component of cathodic arc. The ions loss up to 80 % of their energy resulted by the paired elastic collisions which correspond to the experimental results. The ion fluxes arriving at the surface of the substrates during planetary rotating of them opposite the evaporators mounted to each other at an angle of 120° characterized by the wide range of mutual overlapping.

APA, Harvard, Vancouver, ISO, and other styles

29

Peng, Yong-Lun, Xiao-Ying Han, Min-Sheng Wang, and Jia-Ming Li. "A theoretical study of dielectronic recombination processes of C2+ions in planetary nebulae." Journal of Physics B: Atomic, Molecular and Optical Physics 38, no. 21 (October 11, 2005): 3825–39. http://dx.doi.org/10.1088/0953-4075/38/21/005.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Szegö, K., S. Klimov, G. Kotova, S. Livi, K. Quest, W. Riedler, H. Rosenbauer, et al. "The interaction of the shocked solar wind and the planetary ions at Mars." Advances in Space Research 20, no. 2 (January 1997): 159–67. http://dx.doi.org/10.1016/s0273-1177(97)00527-9.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Medina, Selene, and Miriam Peña. "Expansion Velocities From Different Ions of Planetary Nebulae with [WC]-Type Central Stars." Symposium - International Astronomical Union 209 (2003): 545–46. http://dx.doi.org/10.1017/s0074180900209662.

Full text

Abstract:

High resolution spectroscopic data of a sample consisting of 24 planetary nebulae (PNe) with WR-type nuclei ([WC]) from the list of Tylenda et al. (1993) plus 1 late-[WC] presented by De Marco et al. (2001), and 7 PNe with weak emission line stars (WELS) nuclei listed in Tylenda et al. (1993) are analyzed. The data were collected using the 2.1 m telescope at the Observatorio Astronómico Nacional, San Pedro Mártir, México and were used to determine the expansion velocity (Vexp) of the gaseous component in each sample object in the following ions: [N II]λA6584, [O II]λ3729, [O III]λA5007, Hβ, HeI λ5876, and HeII λ4686. A sample of 8 non-WR type (typical) PNe were observed as a controlo sample. All observational data were systematically gathered using the REOSC Echelle Spectrograph on 1995 July 29–31, 1996 June 14–17, 1997 August 3–4, 1998 December 11–14, 1999 October 4–7, and 2000 November 1–3. In order to take the highest Vexp of the gesous component in each ion, it was taken the half width of the line at one tenth of the maximum intensity when the line featured either a single Gaussian profile or a Gaussian with extended wings profile. For two-peaks profiles, Vexp was measured taking into account both the peak-to-peak displacement and the HW of the lines.

APA, Harvard, Vancouver, ISO, and other styles

32

Sebastianelli, F., and F. A. Gianturco. "Stabilizing dicyanoacetylene anions in planetary atmospheres: quantum dynamics of its transient negative ions." European Physical Journal D 59, no. 3 (June 26, 2010): 389–98. http://dx.doi.org/10.1140/epjd/e2010-00170-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Torres-Peimbert, Silvia, Anabel Arrieta, and Leonid Georgiev. "Expansion velocities of selected PNe." Proceedings of the International Astronomical Union 7, S283 (July 2011): 512–13. http://dx.doi.org/10.1017/s1743921312012185.

Full text

Abstract:

AbstractIn order to clarify the observed relation between the expansion velocity measured from lines of different ions and their ionization potential, we present kinematical data for several objects. We have measured radial velocities on ESO UVES high dispersion spectra to compare expansion velocities for a set of planetary nebulae.

APA, Harvard, Vancouver, ISO, and other styles

34

Bove, Livia E., and Umbertoluca Ranieri. "Salt- and gas-filled ices under planetary conditions." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 377, no. 2146 (April 15, 2019): 20180262. http://dx.doi.org/10.1098/rsta.2018.0262.

Full text

Abstract:

In recent years, evidence has emerged that solid water can contain substantial amounts of guest species, such as small gas molecules—in gas hydrate structures—or ions—in salty ice structures—and that these ‘filled’ ice structures can be stable under pressures of tens of Gigapascals and temperatures of hundreds of Kelvins. The inclusion of guest species can strongly modify the density, vibrational, diffusive and conductivity properties of ice under high pressure, and promote novel exotic properties. In this review, we discuss our experimental findings and molecular dynamics simulation results on the structures formed by salt- and gas-filled ices, their unusual properties, and the unexpected dynamical phenomena observed under pressure and temperature conditions relevant for planetary interiors modelling. This article is part of the theme issue ‘The physics and chemistry of ice: scaffolding across scales, from the viability of life to the formation of planets’.

APA, Harvard, Vancouver, ISO, and other styles

35

Ahmed, Salwa H., Sama M. Al-Jubouri, Nasser Zouli, Ahmed A. Mohammed, Hasan Shaker Majdi, Issam K. Salih, Muayad Al-shaeli, Ayham M. I. Al-Rahawi, Qusay F. Alsalhy, and Alberto Figoli. "Performance Evaluation of Polyethersulfone Membranes for Competitive Removal of Cd2+, Co2+, and Pb2+ Ions from Simulated Groundwater." Geofluids 2021 (January 4, 2021): 1–11. http://dx.doi.org/10.1155/2021/6654477.

Full text

Abstract:

This paper presents studying the performance of three types of polyethersulfone (PES) membrane for the simultaneous removal of Co2+ ions, Cd2+ ions, and Pb2+ ions from binary and ternary aqueous solutions. Co2+ ions, Cd2+ ions, and Pb2+ ions with two different initial concentrations (e.g., 10 and 50 ppm) were selected as examples of heavy metals that contaminate the groundwater as a result of geological and human activities. This study investigated the effect of types of PES membrane and metal ions concentration on the separation process. For the binary aqueous solutions, the permeation flux of the PES2 membranes was higher for the separation process of solutions containing 50 ppm of Cd2+ ions and 10 ppm of Co2+ ions (24.7 L/m2·h) and Pb2+ ions (23.7 L/m2·h). All the metals in the binary solutions had high rejection when their initial concentration was lower than the initial concentration of the other metal present in the same solution. Using PES2, the maximum rejection of Cd2+ ions was 61.3% when the initial concentrations were 50 ppm Pb2+ ions: 10 ppm Cd2+ ions and 55.4% for Pb2+ ions when the initial concentrations were 10 ppm Pb2+ ions: 50 ppm Cd2+ ions. For the ternary aqueous solutions, the rejection and the permeation flux of the PES membranes increased with decreasing the heavy metal initial concentration. Using PES2, the maximum permeation flux was 21.6 L/m2·h when the initial concentration of the metals was 10 ppm; and the maximum rejection of the metals obtained at initial concentration of 10 ppm was 50.5% for Co2+ ions, 48.3% for Cd2+ ions, and 40% for Pb2+ ions. The results of the filtration process using PES2 of simulated contaminated-groundwater indicated the efficient treatment of groundwater containing Co2+, Cd2+, and Pb2+ ions.

APA, Harvard, Vancouver, ISO, and other styles

36

Jandieri, George, Anzor Gvelesiani, Zhuzhuna Diasamidze, Mzia Diasamidze, and Irma Takidze. "THREE-DIMENSIONAL MAGNETOGRADIENT WAVES IN THE UPPER ATMOSPHERE." JOURNAL OF ADVANCES IN PHYSICS 13, no. 4 (August 1, 2017): 4881–87. http://dx.doi.org/10.24297/jap.v13i5.6122.

Full text

Abstract:

General dispersion equation has been obtained for three-dimensional electromagnetic planetary waves, from which follows, as particular case Khantadze results in one-dimension case. It was shown that partial magnetic field line freezing-in as in one-dimension case lead to the excitation of both â€œfastâ€ and â€œslowâ€ planetary waves, in two-liquid approximation (i.e. at ion drag by neutral particles) they are represent oscillations of magnetized electrons and partially magnetized ions in E region of the ionosphere. In F region of the ionosphere using one-liquid approximation only â€œfastâ€ planetary wave will be generated representing oscillation of medium as a whole. Hence, it was shown that three-dimension magnetogradient planetary waves are exist in all components of the ionosphere, and as exact solutions, with well-known slow short-wave MHD waves, are simple mathematical consequence of the MHD equations for the ionosphere.

APA, Harvard, Vancouver, ISO, and other styles

37

Gedalin, Michael, Nikolai V. Pogorelov, and Vadim Roytershteyn. "Backstreaming Pickup Ions." Astrophysical Journal 910, no. 2 (April 1, 2021): 107. http://dx.doi.org/10.3847/1538-4357/abe62c.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Sauvaud, J. A., R. Lundin, H. Rème, J. P. McFadden, C. Carlson, G. K. Parks, E. Möbius, et al. "Intermittent thermal plasma acceleration linked to sporadic motions of the magnetopause, first Cluster results." Annales Geophysicae 19, no. 10/12 (September 30, 2001): 1523–32. http://dx.doi.org/10.5194/angeo-19-1523-2001.

Full text

Abstract:

Abstract. This paper presents the first observations with Cluster of a very dense population of thermal ionospheric ions (H+, He+, O+) locally "accelerated" perpendicularly to the local magnetic field in a region adjacent to the magnetopause and on its magnetospheric side. The observation periods follow a long period of very weak magnetic activity. Recurrent motions of the magnetopause are, in the presented cases, unexpectedly associated with the appearance inside closed field lines of recurrent energy structures of ionospheric ions with energies in the 5 eV to ~1000 eV range. The heaviest ions were detected with the highest energies. Here, the ion behaviour is interpreted as resulting from local electric field enhancements/decreases which adiabatically enhance/lower the bulk energy of a local dense thermal ion population. This drift effect, which is directly linked to magnetopause motions caused by pressure changes, allows for the thermal ions to overcome the satellite potential and be detected by the suprathermal CIS Cluster experiment. When fast flowing, i.e. when detectable, the density (~ 1 cm-3) of these ions from a terrestrial origin is (in the cases presented here) largely higher than the local density of ions from magnetospheric/plasma sheet origin which poses again the question of the relative importance of solar and ionospheric sources for the magnetospheric plasma even during very quiet magnetic conditions.Key words. Ionosphere (planetary ionosphere; plasma convection) Magnetospheric physics (magnetopause, cusp and boundary layers)

APA, Harvard, Vancouver, ISO, and other styles

39

Keller, Graziela R., Luciana Bianchi, James E. Herald, and Walter J. Maciel. "Grids of synthetic spectra for H-poor central stars of planetary nebulae (CSPNe)." Proceedings of the International Astronomical Union 7, S283 (July 2011): 404–5. http://dx.doi.org/10.1017/s1743921312011647.

Full text

Abstract:

AbstractWe present comprehensive grids of model spectra from far-UV to IR, covering the parameter space of [WC] (Keller et al. 2011) and PG1159 stars. Models are calculated with the CMFGEN code, accounting for non-LTE, line blanketing, wind, clumping, and including ions previously neglected. The grids are available at http://dolomiti.pha.jhu.edu/planetarynebulae.html. We used them to analyse UV and far-UV spectra of NGC6905's and NGC5189's central stars.

APA, Harvard, Vancouver, ISO, and other styles

40

Ahmed, Sana, and Kinsuk Acharyya. "Gas-phase Modeling of the Cometary Coma of Interstellar Comet 2I/Borisov." Astrophysical Journal 923, no. 1 (December 1, 2021): 91. http://dx.doi.org/10.3847/1538-4357/ac2a42.

Full text

Abstract:

Abstract Comet 2I/Borisov is the first interstellar comet observed in the solar system, providing a unique opportunity to understand the physical conditions that prevailed in a distant unknown planetary system. Observations of the comet show that the CO/H2O ratio is higher than that observed in solar system comets at a heliocentric distance r h < 2.5 au. We aim to study the gas-phase coma of comet 2I/Borisov using a multifluid chemical-hydrodynamical model. The gas-phase model includes a host of chemical reactions, with the neutrals, ions, and electrons treated as three separate fluids. Energy exchange between the three fluids due to elastic and inelastic scattering and radiative losses are also considered. Our model results show that in the region of the coma beyond ∼100 km of the nucleus, e−−CO inelastic collisions leading to vibrational excitation of CO causes a loss of energy from the electron fluid. We find a high abundance of CO+ and HCO+ ions, and we show how these two ions affect the creation/destruction rates of other ions such as H2O+, H3O+, N-bearing ions, and large organic ions. We find that the presence of CO leads to a higher abundance of large organic ions and neutrals such as CH 3 OH 2 + , CH 3 OCH 4 + , and CH3OCH3, as compared to a typical H2O-rich solar system comet. We conclude that the presence of a large amount of CO in the coma of comet 2I/Borisov, combined with a low production rate, affects the coma temperature profile and flux of major ionic species significantly.

APA, Harvard, Vancouver, ISO, and other styles

41

Raines, Jim M., Daniel J. Gershman, James A. Slavin, Thomas H. Zurbuchen, Haje Korth, Brian J. Anderson, and Sean C. Solomon. "Structure and dynamics of Mercury's magnetospheric cusp: MESSENGER measurements of protons and planetary ions." Journal of Geophysical Research: Space Physics 119, no. 8 (August 2014): 6587–602. http://dx.doi.org/10.1002/2014ja020120.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Saini, N. S., Kuldeep Singh, and Papihra Sethi. "Interaction of Dust-Acoustic Shock Waves in a Magnetized Dusty Plasma under the Influence of Polarization Force." Laser and Particle Beams 2021 (January 20, 2021): 1–8. http://dx.doi.org/10.1155/2021/6679085.

Full text

Abstract:

The interaction of dust-acoustic (DA) shock waves in a magnetized dusty plasma under the influence of nonextensively modified polarization force is investigated. The plasma model consists of negatively charged dust, Maxwellian electrons, nonextensive ions, and polarization force. In this investigation, we have derived the expression of polarization force in the presence of nonextensive ions and illustrated the head-on collision between two DA shock waves. The extended Poincaré–Lighthill–Kuo (PLK) method is employed to obtain the two-sided Korteweg–de Vries–Burgers (KdVB) equations and phase shifts of two shock waves. The trajectories and phase shifts of negative potential dust-acoustic shock waves after collision are examined. The combined effects of various physical parameters such as polarization force, nonextensivity of ions, viscosity of dust, and magnetic field strength on the phase shifts of DA shock waves have been studied. The present investigation might be useful to study the process of collision of nonlinear structures in space dusty plasma such as planetary rings where non-Maxwellian particles such as nonextensive ions, negatively charged dust, and electrons are present.

APA, Harvard, Vancouver, ISO, and other styles

43

Alrbaihat, Mohammad, Ehab AlShamaileh, and E. Al-Rawajfeh. "Environment-Friendly Synthesis of Feldspar-KH2PO4 Complexes by Mechanochemical Reaction." BOHR International Journal of Material Sciences and Engineering 1, no. 1 (2022): 1–6. http://dx.doi.org/10.54646/bijmse.001.

Full text

Abstract:

Novel materials from Feldspar as clay material and KH2PO4 (KHP) are prepared by grinding in a planetary ball mill in a mechanochemical process, one of the most effective ways to synthesize slow-release fertilizers. In two paths, tests were carried out with (3) weight ratio of Feldspar: KH2PO4 contents, at mill The incorporation of KH2PO4 and the liberation of K+ and PO4 3− ions into solution were assessed at rotating speeds ranging from 200 to 700 rpm for two hours, and at milling periods ranging from 1 h, 2 h, and 3 h. Thermal gravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and ion chromatography (IC) were employed to analyze the produced materials. The results confirmed that the mechanochemistry process is a sustainable chemistry method to produce amorphous Feldspars containing KH2PO4. After dispersing Feldspar and KH2PO4 in water for 24 h, K+ and PO4 3− ions were measured. Based on these studies, it has been demonstrated that intercalated Feldspar could function as a carrier of K+ ions and release PO3− 4 ions as a slow fertilizer.

APA, Harvard, Vancouver, ISO, and other styles

44

Kwon, D. H., and D. W. Savin. "ELECTRON-IMPACT IONIZATION OF P-LIKE IONS FORMING Si-LIKE IONS." Astrophysical Journal 784, no. 1 (February 26, 2014): 13. http://dx.doi.org/10.1088/0004-637x/784/1/13.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Wyckoff, S., and J. Theobald. "Molecular ions in comets." Advances in Space Research 9, no. 3 (1989): 157–61. http://dx.doi.org/10.1016/0273-1177(89)90255-x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Canet, Ada, and Ana I. Gómez de Castro. "Evolution of Earth-like extended exospheres orbiting solar-like stars." Monthly Notices of the Royal Astronomical Society 502, no. 4 (February 22, 2021): 6170–76. http://dx.doi.org/10.1093/mnras/stab492.

Full text

Abstract:

ABSTRACT Recent observations of the Earth’s exosphere revealed the presence of an extended hydrogenic component that could reach distances beyond 40 planetary radii. Detection of similar extended exospheres around Earth-like exoplanets could reveal crucial facts in terms of habitability. The presence of these rarified hydrogen envelopes is extremely dependent on the planetary environment, dominated by the ionizing radiation and plasma winds coming from the host star. Radiation and fast wind particles ionize the uppermost layers of planetary atmospheres, especially for planets orbiting active, young stars. The survival of the produced ions in the exosphere of such planets is subject to the action of the magnetized stellar winds, particularly for unmagnetized bodies. In order to address these star–planet interactions, we have carried out numerical 2.5D ideal MHD simulations using the pluto code to study the dynamical evolution of tenuous, hydrogen-rich, Earth-like extended exospheres for an unmagnetized planet, at different stellar evolutionary stages: from a very young, solar-like star of 0.1 Gyr to a 5.0 Gyr star. For each star–planet configuration, we show that the morphology of extended Earth-like hydrogen exospheres is strongly dependent on the incident stellar winds and the produced ions present in these gaseous envelopes, showing that the ionized component of Earth-like exospheres is quickly swept by the stellar winds of young stars, leading to large bow shock formation for later stellar ages.

APA, Harvard, Vancouver, ISO, and other styles

47

Anagnostopoulos, G. C., G. Argyropoulos, and G. Kaliabetsos. "Spatial distribution of upstream magnetospheric ≥50 keV ions." Annales Geophysicae 18, no. 1 (January 31, 2000): 42–46. http://dx.doi.org/10.1007/s00585-000-0042-x.

Full text

Abstract:

Abstract. We present for the first time a statistical study of \\geq50 keV ion events of a magnetospheric origin upstream from Earth's bow shock. The statistical analysis of the 50-220 keV ion events observed by the IMP-8 spacecraft shows: (1) a dawn-dusk asymmetry in ion distributions, with most events and lower intensities upstream from the quasi-parallel pre-dawn side (4 LT-6 LT) of the bow shock, (2) highest ion fluxes upstream from the nose/dusk side of the bow shock under an almost radial interplanetary magnetic field (IMF) configuration, and (3) a positive correlation of the ion intensities with the solar wind speed and the index of geomagnetic index Kp, with an average solar wind speed as high as 620 km s-1 and values of the index Kp > 2. The statistical results are consistent with (1) preferential leakage of ~50 keV magnetospheric ions from the dusk magnetopause, (2) nearly scatter free motion of ~50 keV ions within the magnetosheath, and (3) final escape of magnetospheric ions from the quasi-parallel dawn side of the bow shock. An additional statistical analysis of higher energy (290-500 keV) upstream ion events also shows a dawn-dusk asymmetry in the occurrence frequency of these events, with the occurrence frequency ranging between ~16%-~34% in the upstream region.Key words. Interplanetary physics (energetic particles; planetary bow shocks)

APA, Harvard, Vancouver, ISO, and other styles

48

Crary, F. J., and F. Bagenal. "Ion cyclotron waves, pickup ions, and Io's neutral exosphere." Journal of Geophysical Research: Space Physics 105, A11 (November 1, 2000): 25379–89. http://dx.doi.org/10.1029/2000ja000055.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Kwok, Sun. "Molecular Evolution from AGB Stars to Planetary Nebulae." Proceedings of the International Astronomical Union 7, S280 (June 2011): 203–15. http://dx.doi.org/10.1017/s1743921311024987.

Full text

Abstract:

AbstractThe late stages of stellar evolution from the Asymptotic Giant Branch (AGB) to planetary nebulae represent the most active phase of molecular synthesis in a star's life. Over 60 molecular species, including inorganics, organics, radicals, chains, rings, and molecular ions have been detected in the circumstellar envelopes of evolved stars. Most interestingly, complex organic compounds of aromatic and aliphatic structures are synthesized over very short time intervals after the end of the AGB. Also appeared during the post-AGB evolution are the unidentified 21 and 30 μm emission features, which are believed to originate from carbonaceous compounds.The circumstellar environment is an ideal laboratory for the testing of theories of chemical synthesis. The distinct spectral behavior among AGB stars, proto-planetary nebulae (PPN), and planetary nebulae (PN) and the short evolutionary time scales that separate these stages pose severe constraints on models. In this paper, we will present an observational summary of the chemical synthesis in the late stages of stellar evolution, discuss chemical and physical processes at work, and speculate on the possible effects these chemical products have on the Galaxy and the Solar System.

APA, Harvard, Vancouver, ISO, and other styles

50

Egan, Hilary, Riku Jarvinen, Yingjuan Ma, and David Brain. "Planetary magnetic field control of ion escape from weakly magnetized planets." Monthly Notices of the Royal Astronomical Society 488, no. 2 (July 3, 2019): 2108–20. http://dx.doi.org/10.1093/mnras/stz1819.

Full text

Abstract:

ABSTRACT Intrinsic magnetic fields have long been thought to shield planets from atmospheric erosion via stellar winds; however, the influence of the plasma environment on atmospheric escape is complex. Here we study the influence of a weak intrinsic dipolar planetary magnetic field on the plasma environment and subsequent ion escape from a Mars-sized planet in a global three-dimensional hybrid simulation. We find that increasing the strength of a planet’s magnetic field enhances ion escape until the magnetic dipole’s standoff distance reaches the induced magnetosphere boundary. After this point increasing the planetary magnetic field begins to inhibit ion escape. This reflects a balance between shielding of the Southern hemisphere from ‘misaligned’ ion pickup forces and trapping of escaping ions by an equatorial plasmasphere. Thus, the planetary magnetic field associated with the peak ion escape rate is critically dependent on the stellar wind pressure. Where possible we have fit power laws for the variation of fundamental parameters (escape rate, escape power, polar cap opening angle, and effective interaction area) with magnetic field, and assessed upper and lower limits for the relationships.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Planetary ions'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles