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Journal articles on the topic 'Near field magnetic enhancement'

Author: Grafiati

Published: 28 June 2021

Last updated: 9 February 2022

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1

Liberal, Iñigo, Yue Li, and Nader Engheta. "Magnetic field concentration assisted by epsilon-near-zero media." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 375, no. 2090 (March 28, 2017): 20160059. http://dx.doi.org/10.1098/rsta.2016.0059.

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Strengthening the magnetic response of matter at optical frequencies is of fundamental interest, as it provides additional information in spectroscopy, as well as alternative mechanisms to manipulate light at the nanoscale. Here, we demonstrate theoretically that epsilon-near-zero (ENZ) media can enhance the magnetic field concentration capabilities of dielectric resonators. We demonstrate that the magnetic field enhancement factor is unbounded in theory, and it diverges as the size of the ENZ host increases. In practice, the maximal enhancement factor is limited by dissipation losses in the host, and it is found via numerical simulations that ENZ hosts with moderate losses can enhance the performance of a circular dielectric rod resonator by around one order of magnitude. The physical mechanism behind this process is the strongly inhomogeneous magnetic field distributions induced by ENZ media in neighbouring dielectrics. We show that this is an intrinsic property of ENZ media, and that the occurrence of resonant enhancement is independent of the shape of the host. These results might find applications in spectroscopy, in sensing, in light emission and, in general, in investigating light–matter interactions beyond electric dipole transitions. This article is part of the themed issue ‘New horizons for nanophotonics’.

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2

Leitão, D. C., I. G. Trindade, R. Fermento, João P. Araújo, S. Cardoso, P. P. Freitas, and João Bessa Sousa. "Magnetic Field Enhancement with Soft Magnetic Flux Guides." Materials Science Forum 587-588 (June 2008): 313–17. http://dx.doi.org/10.4028/www.scientific.net/msf.587-588.313.

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In this work, a study of the sensitivity enhancement of spin valve sensors, when located in close proximity to magnetic flux guides, is presented. The magnetoresistance (MR) of spin-valve sensors, lithographically patterned into stripes with lateral dimensions, (length) l = 500 µm, (width) wsensor = 1, 2, 6 µm and placed near one/two Co93.5Zr2.8Nb3.7 (CZN) magnetic flux guide, is characterized at room temperature. CZN has a high permeability that together with a defined microstructured shape, is able to concentrate the magnetic flux in a small area, leading to an increase in sensor's sensitivity. The magnetic field amplification is estimated by comparison of sensor sensitivity with/without magnetic flux guides, in the linear operation range, and studied as a function of different parameters. Besides an enhancement in sensitivity, sensors also exhibit an important increase in the hard axis coercivity and a shift from MR(H=0) = 0.5, both attributed to the magnetic flux guides. Amplification factors of the order of 20 are observed..

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3

Sanz-Fernández, Juan José. "Near-field enhancement for infrared sensor applications." Journal of Nanophotonics 5, no. 1 (January 1, 2011): 051814. http://dx.doi.org/10.1117/1.3604785.

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4

Sun, T. R., C. Wang, N. L. Borodkova, and G. N. Zastenker. "Geosynchronous magnetic field responses to fast solar wind dynamic pressure enhancements: MHD field model." Annales Geophysicae 30, no. 8 (August 27, 2012): 1285–95. http://dx.doi.org/10.5194/angeo-30-1285-2012.

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Abstract. We performed global MHD simulations of the geosynchronous magnetic field in response to fast solar wind dynamic pressure (Pd) enhancements. Taking three Pd enhancement events in 2000 as examples, we found that the main features of the total field B and the dominant component Bz can be efficiently predicted by the MHD model. The predicted B and Bz varies with local time, with the highest level near noon and a slightly lower level around mid-night. However, it is more challenging to accurately predict the responses of the smaller component at the geosynchronous orbit (i.e., Bx and By). In contrast, the limitations of T01 model in predicting responses to fast Pd enhancements are presented.

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5

Bohn, John L., D. J. Nesbitt, and A. Gallagher. "Field enhancement in apertureless near-field scanning optical microscopy." Journal of the Optical Society of America A 18, no. 12 (December 1, 2001): 2998. http://dx.doi.org/10.1364/josaa.18.002998.

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6

Lee, Jaejoon, and Jaewook Lee. "Magnetic Force Enhancement Using Air-Gap Magnetic Field Manipulation by Optimized Coil Currents." Applied Sciences 10, no. 1 (December 21, 2019): 104. http://dx.doi.org/10.3390/app10010104.

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This paper presents an air-gap magnetic field manipulation by optimized coil currents for a magnetic force enhancement in electromechanical devices. The external coil is designed near the device air-gap for manipulating the magnetic field distribution. The distribution of external coil currents is then optimized for maximizing the magnetic force in the tangential direction to the air-gap line. For the optimization, the design domain near air-gap is divided into small areas, and design variables are assigned at each small design area. The design variables determines not only the strength of coil current density (i.e., number of coil turns) but also whether the material state is coil or iron. In a benchmark actuator example, it is shown that 11.12% force enhancement is available by manipulating the air-gap magnetic field distribution using the optimized coil current. By investigating the magnetic field distribution, it is confirmed that the optimized coil current manipulated the magnetic field, forwarding a focused and inclined distribution that is an ideal distribution for maximizing the magnetic force.

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7

Furukawa, Hiromitsu, and Satoshi Kawata. "Local field enhancement with an apertureless near-field-microscope probe." Optics Communications 148, no. 4-6 (March 1998): 221–24. http://dx.doi.org/10.1016/s0030-4018(97)00687-1.

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8

Encina, Ezequiel R., and Eduardo A. Coronado. "Near Field Enhancement in Ag Au Nanospheres Heterodimers." Journal of Physical Chemistry C 115, no. 32 (July 22, 2011): 15908–14. http://dx.doi.org/10.1021/jp205158w.

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9

Granitzka, Patrick W., Emmanuelle Jal, Loïc Le Guyader, Matteo Savoini, Daniel J. Higley, Tianmin Liu, Zhao Chen, et al. "Magnetic Switching in Granular FePt Layers Promoted by Near-Field Laser Enhancement." Nano Letters 17, no. 4 (March 17, 2017): 2426–32. http://dx.doi.org/10.1021/acs.nanolett.7b00052.

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10

Aksyuk, Vladimir, Basudev Lahiri, Glenn Holland, and Andrea Centrone. "Near-field asymmetries in plasmonic resonators." Nanoscale 7, no. 8 (2015): 3634–44. http://dx.doi.org/10.1039/c4nr06755j.

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11

Ji, Fengtong, Ben Wang, and Li Zhang. "Light-Triggered Catalytic Performance Enhancement Using Magnetic Nanomotor Ensembles." Research 2020 (July 8, 2020): 1–11. http://dx.doi.org/10.34133/2020/6380794.

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Micro/nanomachines have attracted extensive attention in the biomedical and environmental fields for realizing functionalities at small scales. However, they have been rarely investigated as active nanocatalysts. Heterogeneous nanocatalysts have exceptional reusability and recyclability, and integration with magnetic materials enables their recovery with minimum loss. Herein, we propose a model active nanocatalyst using magnetic nanomotor ensembles (MNEs) that can degrade contaminants in an aqueous solution with high catalytic performance. MNEs composed of a magnetite core coated with gold nanoparticles as the nanocatalyst can rotate under the action of a programmable external field and carry out rapid reduction of 4-nitrophenol (4-NP). The hydrogen bubbles generated in the catalytic reaction provide random perturbations for the MNEs to travel in the reaction solution, resulting in uniform processing. The reduction can be further boosted by irradiation with near-infrared (NIR) light. Magnetic field induces the rotation of the MNEs and provides microstirring in the catalysis. Light enhances the catalytic activity via the photothermal effect. These MNEs are also capable of moving to the targeted region through the application of a programmable magnetic field and then process the contaminant in the targeted region. We expect that such magnetic MNEs may help better in applying active heterogeneous nanocatalysts with magnetic field and light-enhanced performance in industrial applications due to their advantages of low material cost and short reaction time.

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12

Gosciniak, Jacek, Marcus Mooney, Mark Gubbins, and Brian Corbett. "Novel droplet near-field transducer for heat-assisted magnetic recording." Nanophotonics 4, no. 4 (December 30, 2015): 503–10. http://dx.doi.org/10.1515/nanoph-2015-0031.

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AbstractTwo main ingredients of plasmonics are surface plasmon polaritons (SPP) and localized surface plasmon resonances (LSPR) as they provide a high degree of concentration of electromagnetic fields in the vicinity of metal surfaces, which is well beyond that allowed by the diffraction limit of optics. Those properties have been used in the new technique of heat assisted magnetic recording (HAMR) to overcome an existing limit of conventional magnetic recording by utilizing a near-field transducer (NFT). The NFT designs are based on excitation of surface plasmons on a metal structure, which re-radiate with a subdiffraction limited light spot confined in the near field. In this paper, we propose a novel “droplet”-shaped NFT, which takes full advantage of a recenltly proposed Mach–Zehnder Interferometer (MZI), a coupling arrangement that allows optimal coupling of light to the transducer. The droplet design ensures better impedance match with the recording media and, consequently, better coupling of power. The droplet design results in very high enhancement of the electric field and allows the confinement of light in a spot size much smaller than the present stateof- the-art lollipop transducer.

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13

Biswas, Debabrata, Gaurav Singh, Shreya G. Sarkar, and Raghwendra Kumar. "Variation of field enhancement factor near the emitter tip." Ultramicroscopy 185 (February 2018): 1–4. http://dx.doi.org/10.1016/j.ultramic.2017.10.016.

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14

Kuri, Deep Kumar, Nilakshi Das, and Kartik Patel. "Collimated proton beams from magnetized near-critical plasmas." Laser and Particle Beams 36, no. 3 (August 31, 2018): 276–85. http://dx.doi.org/10.1017/s0263034618000307.

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AbstractGeneration of collimated proton beams by linearly and circularly polarized (CP) lasers from magnetized near-critical plasmas has been investigated with the help of three-dimensional (3D) particle-in-cell (PIC) simulations. Due to cyclotron effects, the transverse proton momentum gets significantly reduced in the presence of an axial magnetic field which leads to an enhancement in collimation. Collimation is observed to be highest in case of a linearly polarized (LP) laser in the presence of magnetic field. However, protons accelerated by a right CP laser in the presence of magnetic field are not only highly collimated but are also more energetic than those accelerated by the LP laser. Although, the presence of an axial magnetic field enhances the collimation by reducing the transverse proton momentum, the maximum proton energy gets reduced since the transverse proton momentum has a significant contribution towards proton energy.

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15

Choi, Soo Bong, Doo Jae Park, Sun Jung Byun, Jisoo Kyoung, and Sung Woo Hwang. "Near-Zero Index: Optical Magnetic Mirror for Field Enhancement and Subwavelength Imaging Applications." Advanced Optical Materials 3, no. 12 (August 18, 2015): 1719–25. http://dx.doi.org/10.1002/adom.201500294.

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16

KAWATA, SATOSHI, TARO ICHIMURA, NORIHIKO HAYAZAWA, YASUSHI INOUYE, and MAMORU HASHIMOTO. "TIP-ENHANCED NEAR-FIELD CARS MICROSCOPY." Journal of Nonlinear Optical Physics & Materials 13, no. 03n04 (December 2004): 593–99. http://dx.doi.org/10.1142/s0218863504002341.

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We apply the field enhancement effect due to plasmon polariton excitation on a metallic nanostructure in order to improve the diffraction limited spatial resolution of coherent anti-Stokes Raman scattering (CARS) microscopy. A cantilever probe tip coated with a 25 nm-thick gold film is utilized as a near-field light source to locally excite the CARS polarizations near the tip. Our CARS microscope has effectively enhanced the CARS signals and realized vibrational imaging of single-wall carbon nanotubes (SWNTs) beyond the spatial resolution of far-field CARS microscopy.

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17

Kallio, E., S. McKenna-Lawlor, M. Alho, R. Jarvinen, S. Dyadechkin, and V. V. Afonin. "Energetic protons at Mars: interpretation of SLED/Phobos-2 observations by a kinetic model." Annales Geophysicae 30, no. 11 (November 27, 2012): 1595–609. http://dx.doi.org/10.5194/angeo-30-1595-2012.

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Abstract. Mars has neither a significant global intrinsic magnetic field nor a dense atmosphere. Therefore, solar energetic particles (SEPs) from the Sun can penetrate close to the planet (under some circumstances reaching the surface). On 13 March 1989 the SLED instrument aboard the Phobos-2 spacecraft recorded the presence of SEPs near Mars while traversing a circular orbit (at 2.8 RM). In the present study the response of the Martian plasma environment to SEP impingement on 13 March was simulated using a kinetic model. The electric and magnetic fields were derived using a 3-D self-consistent hybrid model (HYB-Mars) where ions are modelled as particles while electrons form a massless charge neutralizing fluid. The case study shows that the model successfully reproduced several of the observed features of the in situ observations: (1) a flux enhancement near the inbound bow shock, (2) the formation of a magnetic shadow where the energetic particle flux was decreased relative to its solar wind values, (3) the energy dependency of the flux enhancement near the bow shock and (4) how the size of the magnetic shadow depends on the incident particle energy. Overall, it is demonstrated that the Martian magnetic field environment resulting from the Mars–solar wind interaction significantly modulated the Martian energetic particle environment.

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18

Foster, J. C., and W. Rideout. "Storm enhanced density: magnetic conjugacy effects." Annales Geophysicae 25, no. 8 (August 29, 2007): 1791–99. http://dx.doi.org/10.5194/angeo-25-1791-2007.

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Abstract. In the early phases of a geomagnetic storm, the low and mid-latitude ionosphere are greatly perturbed. Large SAPS electric fields map earthward from the perturbed ring current overlapping and eroding the outer plasmasphere and mid-latitude ionosphere, drawing out extended plumes of storm enhanced density (SED). We use combined satellite and ground-based observations to investigate the degree of magnetic conjugacy associated with specific features of the stormtime ionospheric perturbation. We find that many ionospheric disturbance features exhibit degrees of magnetic conjugacy and simultaneity which implicate the workings of electric fields. TEC enhancements on inner-magnetospheric field lines at the base of the SED plumes exhibit localized and longitude-dependent features which are not strictly magnetic conjugate. The SED plumes streaming away from these source regions closely follow magnetic conjugate paths. SED plumes can be used as a tracer of the location and strength of disturbance electric fields. The SED streams of cold plasma from lower latitudes enter the polar caps near noon, forming conjugate tongues of ionization over the polar regions. SED plumes exhibit close magnetic conjugacy, confirming that SED is a convection electric field dominated effect. Several conclusions are reached: 1) The SED plume occurs in magnetically-conjugate regions in both hemispheres. 2) The position of the sharp poleward edge of the SED plume is closely conjugate. 3) The SAPS electric field is observed in magnetically conjugate regions (SAPS channel). 4) The strong TEC enhancement at the base of the SED plume in the north American sector is more extensive than in its magnetic conjugate region. 5) The entry of the SED plume into the polar cap near noon, forming the polar tongue of ionization (TOI), is seen in both hemispheres in magnetically-conjugate regions.

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19

Rai, V. N., M. Shukla, and H. C. Pant. "Some studies on picosecond laser produced plasma expanding across a uniform external magnetic field." Laser and Particle Beams 16, no. 3 (September 1998): 431–43. http://dx.doi.org/10.1017/s0263034600011265.

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Some characteristics of the picosecond laser produced plasma expanding across an externally applied magnetic field (0.6T) have been reported. Two to three times enhancement in X-ray emission from copper plasma has been observed for the laser intensity range ∼5 X 1011 to 5 X 1012 W/cm2. The X-ray yield has been found to increase with an increase in the magnetic field intensity. Enhancement in X-ray emission is correlated with confinement of expanding plasma either in external magnetic field or in high ambient gas pressure. Generation of some highfrequency instability and fast ions was also observed in the plasma along with bouncing of plasma near the β = 1 surface where kinetic pressure of plasma equals magnetic pressure.

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20

Pint�r, S., K. Kecsem�ty, and A. Varga. "Unusual enhancement of galactic cosmic-ray intensity near an interplanetary magnetic field annihilation region." Solar Physics 106, no. 1 (July 1986): 201–4. http://dx.doi.org/10.1007/bf00161363.

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21

Wood, A. G., S. E. Pryse, H. R. Middleton, and V. S. C. Howells. "Multi-instrument observations of nightside plasma patches under conditions of IMF <I>B<sub>z</sub></I> positive." Annales Geophysicae 26, no. 8 (August 5, 2008): 2203–16. http://dx.doi.org/10.5194/angeo-26-2203-2008.

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Abstract. Results are presented from two multi-instrument case studies showing patches of cold, long-lived plasma in the winter nightside ionosphere during times when the z-component of the Interplanetary Magnetic Field (IMF Bz) was positive. These enhancements were coincident with the antisunward convective plasma drift, flowing from polar to nightside auroral latitudes. In the first case, on 5 December 2005 with IMF By negative, two regions of enhanced electron density were observed extended in MLT in the magnetic midnight sector separated by lower densities near midnight. It is likely that the earlier enhancement originated on the dayside near magnetic noon and was transported to the nightside sector in the convective flow, whilst the later feature originated in the morning magnetic sector. The lower densities separating the two enhancements were a consequence of a pair of lobe cells essentially blocking the direct antisunward cross polar flow from the dayside. A second case study on 4 February 2006 with IMF By positive revealed a single nightside enhancement likely to have originated in the morning magnetic sector. These multi-instrument investigations, incorporating observations by the EISCAT radar facility, the SuperDARN network and radio tomography, reveal that plasma flowing from the dayside can play a significant role in the nightside ionosphere under conditions of IMF Bz positive. The observations are reinforced by simulations of flux-tube transport and plasma decay.

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22

Mignuzzi, Sandro, Fumin Huang, Debdulal Roy, and David Richards. "Near-Field Raman Enhancement of Single Molecules and Point Scatterers." Journal of Physical Chemistry C 121, no. 34 (August 17, 2017): 18800–18806. http://dx.doi.org/10.1021/acs.jpcc.7b03965.

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23

Keszthelyi, Z., G. Meynet, C. Georgy, G. A. Wade, V. Petit, and A. David-Uraz. "The effects of surface fossil magnetic fields on massive star evolution: I. Magnetic field evolution, mass-loss quenching, and magnetic braking." Monthly Notices of the Royal Astronomical Society 485, no. 4 (March 20, 2019): 5843–60. http://dx.doi.org/10.1093/mnras/stz772.

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Abstract Surface magnetic fields have a strong impact on stellar mass loss and rotation and, as a consequence, on the evolution of massive stars. In this work, we study the influence of an evolving dipolar surface fossil magnetic field with an initial field strength of 4 kG on the characteristics of 15 M⊙ solar metallicity models using the Geneva stellar evolution code. Non-rotating and rotating models considering two different scenarios for internal angular momentum transport are computed, including magnetic field evolution, mass-loss quenching, and magnetic braking. Magnetic field evolution results in weakening the initially strong magnetic field; however, in our models, an observable magnetic field is still maintained as the star evolves towards the red supergiant phase. At the given initial mass of the models, mass-loss quenching is modest. Magnetic braking greatly enhances chemical element mixing if radial differential rotation is allowed for; on the other hand, the inclusion of surface magnetic fields yields a lower surface enrichment in the case of near solid-body rotation. Models including surface magnetic fields show notably different trends on the Hunter diagram (plotting nitrogen abundance versus vsin i) compared to those that do not. The magnetic models agree qualitatively with the anomalous ‘Group 2 stars’, showing slow surface rotation and high surface nitrogen enhancement on the main sequence.

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24

LIU, S. Q., and X. Q. LI. "Numerical analysis of self-generated magnetic field excited by transverse plasmons in a laser-produced plasma." Journal of Plasma Physics 66, no. 4 (October 2001): 223–38. http://dx.doi.org/10.1017/s0022377801001210.

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Abstract. We study numerically the collapse behavior of self-generated magnetic fields described by the nonlinear coupling equations in laser-produced plasmas. The results show that magnetic fields self-generated by transverse pumping plasmons near critical points may collapse, leading to the enhancement of magnetic fields about up to 0.18 MG and 1.8 MG at laser irradiances of 1012 W cm−2 and 1016 W cm−2 respectively, which are similar to the experimental results.

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25

Tu, C. Y., E. Marsch, K. Ivory, and R. Schwenn. "Pressure enhancement associated with meridional flow in high-speed solar wind: possible evidence for an interplanetary magnetic flux rope." Annales Geophysicae 15, no. 2 (February 28, 1997): 137–42. http://dx.doi.org/10.1007/s00585-997-0137-8.

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Abstract. A sizable total-pressure (magnetic pressure plus kinetic pressure) enhancement was found within the high-speed wind stream observed by Helios 2 in 1976 near 0.3 AU. The proton density and temperature and the magnetic magnitude simultaneously increased for about 6 h. This pressure rise was associated with a comparatively large southward flow velocity component (with Vz ≈ –100 km · s–1) and magnetic-field rotation. The pressure enhancement was associated with unusual features in the electron distribution function. It shows a wide angular distribution of electron counting rates in the low-energy (57.8 eV) channel, while previous to the enhancement it exhibits a wide angular distribution of electron count rate in the high-energy (112, 221 and 309 eV) channels, perhaps indicating the mirroring of electrons in the converging field lines of the background magnetic field. These fluid and kinetic phenomena may be explained as resulting from an interplanetary magnetic flux rope which is not fully convected by the flow but moves against the background wind towards the Sun.

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26

Proctor, Matthew, Xiaofei Xiao, Richard V. Craster, Stefan A. Maier, Vincenzo Giannini, and Paloma Arroyo Huidobro. "Near- and Far-Field Excitation of Topological Plasmonic Metasurfaces." Photonics 7, no. 4 (September 24, 2020): 81. http://dx.doi.org/10.3390/photonics7040081.

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The breathing honeycomb lattice hosts a topologically non-trivial bulk phase due to the crystalline-symmetry of the system. Pseudospin-dependent edge states, which emerge at the interface between trivial and non-trivial regions, can be used for the directional propagation of energy. Using the plasmonic metasurface as an example system, we probe these states in the near- and far-field using a semi-analytical model. We provide the conditions under which directionality was observed and show that it is source position dependent. By probing with circularly-polarised magnetic dipoles out of the plane, we first characterise modes along the interface in terms of the enhancement of source emissions due to the metasurface. We then excite from the far-field with non-zero orbital angular momentum beams. The position-dependent directionality holds true for all classical wave systems with a breathing honeycomb lattice. Our results show that a metasurface in combination with a chiral two-dimensional material, could be used to guide light effectively on the nanoscale.

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27

Belenkaya, E. S., I. I. Alexeev, and C. R. Clauer. "Magnetic field of the transition current system: dawn-dusk asymmetry." Annales Geophysicae 25, no. 8 (August 29, 2007): 1899–911. http://dx.doi.org/10.5194/angeo-25-1899-2007.

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Abstract. In this paper we consider the interactions of coronal mass ejections (CMEs) with the Earth's magnetosphere for the specific case in which there is a sharp increase in the dynamic pressure (interplanetary shock) that is associated with a simultaneous northward turning of the interplanetary magnetic field (IMF) from the near horizontal direction. Previously, we have shown that under such circumstances, the so-called transition current systems arise. These temporary high-latitude current systems create a low-latitude asymmetric magnetic field on the ground with a large northward field enhancement on the nightside and little or no field increase near local noon. Here we investigate the dawn-dusk asymmetry of the low-latitude on-ground magnetic field of the transition current system caused by the IMF. Analysis of the Region 1 current circuit for northward IMF shows a change in its shape controlled by different IMF components. Due to this geometrical effect, the maximum and minimum magnetic field disturbances appear to be shifted. The obtained results supplement and define more precisely the locations of the magnetic disturbance extrema retrieved recently by Clauer et al. (2001). The results of this study are compared with the available observations. A good accordance is demonstrated.

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Wu, DaJian, HaiQun Yu, Jie Yao, QingYu Ma, Ying Cheng, and XiaoJun Liu. "Efficient Magnetic Resonance Amplification and Near-Field Enhancement from Gain-Assisted Silicon Nanospheres and Nanoshells." Journal of Physical Chemistry C 120, no. 24 (June 14, 2016): 13227–33. http://dx.doi.org/10.1021/acs.jpcc.6b03871.

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29

Weaver, Katherine E., Fei Wang, and Akhlesh Lakhtakia. "Enhancement of near-field phase-shifting contact lithography by immersion technique." Optik 117, no. 4 (April 2006): 183–87. http://dx.doi.org/10.1016/j.ijleo.2005.08.007.

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30

Lekner, John. "Near approach of two conducting spheres: Enhancement of external electric field." Journal of Electrostatics 69, no. 6 (December 2011): 559–63. http://dx.doi.org/10.1016/j.elstat.2011.07.009.

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31

Wang, Puqun, Sara Azimi, Mark B. H. Breese, and Marius Peters. "Near-field enhancement of periodic nanostructures for photovoltaic applications: a theoretical study." Journal of Optics 16, no. 12 (November 27, 2014): 125012. http://dx.doi.org/10.1088/2040-8978/16/12/125012.

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32

Douas, Maysoun, Manuel I. Marqués, and Pedro A. Serena. "Optical image contrast enhancement in near-field optics induced by water condensation." Ultramicroscopy 135 (December 2013): 50–55. http://dx.doi.org/10.1016/j.ultramic.2013.05.021.

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33

Lim, Dong-Soo, Hyun-Suk Oh, and Young-Joo Kim. "Near-Field Optical Coupling and Enhancement in Surface Plasmon Assisted Media for Heat Assisted Magnetic Recording." Japanese Journal of Applied Physics 48, no. 3 (March 23, 2009): 03A059. http://dx.doi.org/10.1143/jjap.48.03a059.

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34

Das, Barnali, Poonam Chandra, Matt E. Shultz, and Gregg A. Wade. "The fifth main-sequence magnetic B-type star showing coherent radio emission: Is this really a rare phenomenon?" Monthly Notices of the Royal Astronomical Society: Letters 489, no. 1 (September 5, 2019): L102—L107. http://dx.doi.org/10.1093/mnrasl/slz137.

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ABSTRACT We report the discovery of intense, highly directional radio emission from the Bp star HD 35298, which we interpret as the consequence of Electron Cyclotron Maser Emission (ECME). The star was observed with the Giant Metrewave Radio Telescope near the rotational phases of both magnetic nulls in band 4 (550–750 MHz) and one of the nulls in band 5 (1060–1460 MHz). In band 4, we observed flux density enhancement in both circular polarizations near both magnetic nulls. The sequences of arrival of the left and right circularly polarized pulses are opposite near the two nulls. In band 5, we did not have circular polarization information and hence measured only the total intensity light curve, which also shows enhancement around the magnetic null. The observed sequence of the circular polarization signs in band 4, compared with the longitudinal magnetic field curve, is able to locate the hemisphere from which ECME arises. This observational evidence supports the scenario of ECME in the ordinary mode, arising in a magnetosphere shaped like an oblique dipole. HD 35298 is the most slowly rotating and most distant main-sequence magnetic star from which ECME has been observed.

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35

Wada, Kengo, Masayuki Kaneda, and Kazuhiko Suga. "Rayleigh-Bénard Convection of Paramagnetic Liquid under a Magnetic Field from Permanent Magnets." Symmetry 12, no. 3 (February 28, 2020): 341. http://dx.doi.org/10.3390/sym12030341.

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The convection control is important in terms of the heat transfer enhancement and improvement of the applied devices and resultant products. In this study, the convection control by a magnetic field from block permanent magnets is numerically investigated on the Rayleigh-Bénard convection of paramagnetic fluid. To enhance the magnetic force from the available permanent magnets, pairs of alternating-pole magnets are employed and aligned near the bottom heated wall. The lattice Boltzmann method is employed for the computation of the heat and fluid flow with the consideration of buoyancy and magnetothermal force on the working fluid. It is found that, since the magnetic force at the junction of pair magnets becomes strong remarkably and in the same direction as the gravity, descending convection flow is locally enhanced and the pair of symmetrical roll cells near the magnet junction becomes longitudinal. The local heat transfer corresponds to the affected roll cell pattern; locally enhanced at the magnet junctions and low heat transfer area is shifted aside the magnet outer edge. The averaged Nusselt number on the hot wall also increases proportionally to the magnetic induction but it is saturated at high magnetic induction. This suggests the roll cell pattern is no more largely affected at extremely-high magnetic induction.

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36

Guzman, Federico V., Pablo A. Mercadal, Eduardo A. Coronado, and Ezequiel R. Encina. "Near-Field Enhancement Contribution to the Photoactivity in Magnetite–Gold Hybrid Nanostructures." Journal of Physical Chemistry C 123, no. 49 (November 20, 2019): 29891–99. http://dx.doi.org/10.1021/acs.jpcc.9b09421.

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Fischer, Janina, Noelia Bocchio, Andreas Unger, Hans-Jürgen Butt, Kaloian Koynov, and Maximilian Kreiter. "Near-Field-Mediated Enhancement of Two-Photon-Induced Fluorescence on Plasmonic Nanostructures." Journal of Physical Chemistry C 114, no. 49 (November 17, 2010): 20968–73. http://dx.doi.org/10.1021/jp105339b.

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38

Tsunomura, S. "Numerical analysis of global ionospheric current system including the effect of equatorial enhancement." Annales Geophysicae 17, no. 5 (May 31, 1999): 692–706. http://dx.doi.org/10.1007/s00585-999-0692-2.

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Abstract. A modeling method is proposed to derive a two-dimensional ionospheric layer conductivity, which is appropriate to obtain a realistic solution of the polar-originating ionospheric current system including equatorial enhancement. The model can be obtained by modifying the conventional, thin shell conductivity model. It is shown that the modification for one of the non-diagonal terms (Σθφ) in the conductivity tensor near the equatorial region is very important; the term influences the profile of the ionospheric electric field around the equator drastically. The proposed model can reproduce well the results representing the observed electric and magnetic field signatures of geomagnetic sudden commencement. The new model is applied to two factors concerning polar-originating ionospheric current systems. First, the latitudinal profile of the DP2 amplitude in the daytime is examined, changing the canceling rate for the dawn-to-dusk electric field by the region 2 field-aligned current. It is shown that the equatorial enhancement would not appear when the ratio of the total amount of the region 2 field-aligned current to that of region 1 exceeds 0.5. Second, the north-south asymmetry of the magnetic fields in the summer solstice condition of the ionospheric conductivity is examined by calculating the global ionospheric current system covering both hemispheres simultaneously. It is shown that the positive relationship between the magnitudes of high latitude magnetic fields and the conductivity is clearly seen if a voltage generator is given as the source, while the relationship is vague or even reversed for a current generator. The new model, based on the International Reference Ionosphere (IRI) model, can be applied to further investigations in the quantitative analysis of the magnetosphere-ionosphere coupling problems.Key words. Ionosphere (electric fields and currents; equatorial ionosphere; ionosphere-magnetosphere interactions)

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39

Zhou, Xinfeng, Xuguang Guo, Alexander Shkurinov, and Yiming Zhu. "Concentric-ring-grating-induced strong terahertz near-field enhancement on a micro-tip." Journal of Optics 21, no. 10 (September 20, 2019): 105005. http://dx.doi.org/10.1088/2040-8986/ab3d7e.

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40

Belova, E., S. Kirkwood, and H. Tammet. "The effect of magnetic substorms on near-ground atmospheric current." Annales Geophysicae 18, no. 12 (December 31, 2000): 1623–29. http://dx.doi.org/10.1007/s00585-001-1623-z.

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Abstract. Ionosphere-magnetosphere disturbances at high latitudes, e.g. magnetic substorms, are accompanied by energetic particle precipitation and strong variations of the ionospheric electric fields and currents. These might reasonably be expected to modify the local atmospheric electric circuit. We have analysed air-earth vertical currents (AECs) measured by a long wire antenna at Esrange, northern Sweden during 35 geomagnetic substorms. Using superposed epoch analysis we compare the air-earth current variations during the 3 h before and after the time of the magnetic X-component minimum with those for corresponding local times on 35 days without substorms. After elimination of the average daily variation we can conclude that the effect of substorms on AEC is small but distinguishable. It is speculated that the AEC increases observed during about 2 h prior to the geomagnetic X-component minimum, are due to enhancement of the ionospheric electric field. During the subsequent 2 h of the substorm recovery phase, the difference between "substorm" and "quiet" atmospheric currents decreases. The amplitude of this "substorm" variation of AEC is estimated to be less than 50% of the amplitude of the diurnal variation in AEC during the same time interval. The statistical significance of this result was confirmed using the Van der Waerden X-test. This method was further used to show that the average air-earth current and its fluctuations increase during late expansion and early recovery phases of substorms.Key words: Ionosphere (electric fields and currents) · Magnetospheric physics (storms and substorms) · Meteorology and atmospheric dynamics (atmospheric electricity)

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Chen, Yiqin, Yueqiang Hu, Jingyi Zhao, Yunsheng Deng, Zhaolong Wang, Xing Cheng, Dangyuan Lei, Yongbo Deng, and Huigao Duan. "Topology Optimization‐Based Inverse Design of Plasmonic Nanodimer with Maximum Near‐Field Enhancement." Advanced Functional Materials 30, no. 23 (April 8, 2020): 2000642. http://dx.doi.org/10.1002/adfm.202000642.

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42

Nicolls, M. J., M. C. Kelley, M. N. Vlasov, Y. Sahai, J. L. Chau, D. L. Hysell, P. R. Fagundes, F. Becker-Guedes, and W. L. C. Lima. "Observations and modeling of post-midnight uplifts near the magnetic equator." Annales Geophysicae 24, no. 5 (July 3, 2006): 1317–31. http://dx.doi.org/10.5194/angeo-24-1317-2006.

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Abstract. We report here on post-midnight uplifts near the magnetic equator. We present observational evidence from digital ionosondes in Brazil, a digisonde in Peru, and other measurements at the Jicamarca Radio Observatory that show that these uplifts occur fairly regularly in the post-midnight period, raising the ionosphere by tens of kilometers in the most mild events and by over a hundred kilometers in the most severe events. We show that in general the uplifts are not the result of a zonal electric field reversal, and demonstrate instead that the uplifts occur as the ionospheric response to a decreasing westward electric field in conjunction with sufficient recombination and plasma flux. The decreasing westward electric field may be caused by a change in the wind system related to the midnight pressure bulge, which is associated with the midnight temperature maximum. In order to agree with observations from Jicamarca and Palmas, Brazil, it is shown that there must exist sufficient horizontal plasma flux associated with the pressure bulge. In addition, we show that the uplifts may be correlated with a secondary maximum in the spread-F occurrence rate in the post-midnight period. The uplifts are strongly seasonally dependent, presumably according to the seasonal dependence of the midnight pressure bulge, which leads to the necessary small westward field in the post-midnight period during certain seasons. We also discuss the enhancement of the uplifts associated with increased geomagnetic activity, which may be related to disturbance dynamo winds. Finally, we show that it is possible using simple numerical techniques to estimate the horizontal plasma flux and the vertical drift velocity from electron density measurements in the post-midnight period.

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43

Taniguchi, Yuji, Kazuma Isobe, and Katsunori Hanamura. "Enhancement of spectrally controlled near-field radiation transfer by magnetic polariton generated by metal–insulator–metal structures." Applied Thermal Engineering 183 (January 2021): 116041. http://dx.doi.org/10.1016/j.applthermaleng.2020.116041.

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44

Wang, Chu, Yu, Gao, and Peng. "Near-Field Enhancement and Polarization Selection of a Nano-System for He-Ne Laser Application." Nanomaterials 9, no. 10 (October 6, 2019): 1421. http://dx.doi.org/10.3390/nano9101421.

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In this paper, we focus on transmission behavior based on the single aperture with a scatter. Both the near-field enhancement and polarization selection can be achieved numerically with a proposed nano-system under He-Ne laser wavelength. The nano-system consists of an Ag antenna, a wafer layer, an Ag film with an aperture and a dielectric substrate. Numerical results show that the near-field enhancement is related to the FP-like resonance base on surface plasmon polaritons (SPPs) in the metal–isolator–metal (MIM) waveguide for transverse magnetic (TM) polarization. The near-field optical spot is confined at the aperture export with a maximal electric intensity 20 times the value of the incident field for an antenna length of 430 nm. The transmission cutoff phenomenon for transverse electric (TE) polarization is because the transmission is forbidden for smaller aperture width. High extinction ratios of 9.6×10-8 (or 70.2 dB) and 4.4×10-8 (or 73.6 dB) with antenna lengths of 130 nm and 430 nm are achieved numerically with the nano-system. The polarization selective property has a good angular tolerance for oblique angles smaller than 15°. The spectral response is also investigated. We further demonstrate that the nano-system is applicable for another incident wavelength of 500 nm. Our investigation may be beneficial for the detection of polar molecules or local nano polarized nanosource.

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Chen, Xu, Yuqian Wang, Zhiwei Guo, Xian Wu, Fengqing Yang, Yong Sun, Yunhui Li, Haitao Jiang, and Hong Chen. "Significant enhancement of magnetic shielding effect by using the composite metamaterial composed of mu-near-zero media and ferrite." EPJ Applied Metamaterials 8 (2021): 13. http://dx.doi.org/10.1051/epjam/2021008.

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The magnetic shield plays an important role in magnetic near-field control. However, the requirements of efficiency, ultra thinness, lightness and cheapness are still the challenges. Here, we firstly propose a composite metamaterial in which the mu-near-zero media is covered with a ferrite slab. We verify that this structure can enhance the shielding effectiveness (SE) in a small area. Furthermore, we optimize the magnetic path by changing the bulk ferrite slab into a patterned slab. In this way, significant SE enhancement can be achieved in a large area. Experimental results show that the maximum SE of the composite metamaterial with a patterned ferrite is 20.56 dB, which is nearly 19 dB higher than that of a single ferrite slab with the same thickness of the composite metamaterial. The results on the composite metamaterial would be very useful in the applications involving magnetic shielding.

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46

Woolley, Thomas, Lorenzo Matteini, Timothy S. Horbury, Stuart D. Bale, Lloyd D. Woodham, Ronan Laker, Benjamin L. Alterman, et al. "Proton core behaviour inside magnetic field switchbacks." Monthly Notices of the Royal Astronomical Society 498, no. 4 (September 11, 2020): 5524–31. http://dx.doi.org/10.1093/mnras/staa2770.

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ABSTRACT During Parker Solar Probe’s first two orbits, there are widespread observations of rapid magnetic field reversals known as switchbacks. These switchbacks are extensively found in the near-Sun solar wind, appear to occur in patches, and have possible links to various phenomena such as magnetic reconnection near the solar surface. As switchbacks are associated with faster plasma flows, we questioned whether they are hotter than the background plasma and whether the microphysics inside a switchback is different to its surroundings. We have studied the reduced distribution functions from the Solar Probe Cup instrument and considered time periods with markedly large angular deflections to compare parallel temperatures inside and outside switchbacks. We have shown that the reduced distribution functions inside switchbacks are consistent with a rigid velocity space rotation of the background plasma. As such, we conclude that the proton core parallel temperature is very similar inside and outside of switchbacks, implying that a temperature–velocity (T–V) relationship does not hold for the proton core parallel temperature inside magnetic field switchbacks. We further conclude that switchbacks are consistent with Alfvénic pulses travelling along open magnetic field lines. The origin of these pulses, however, remains unknown. We also found that there is no obvious link between radial Poynting flux and kinetic energy enhancements suggesting that the radial Poynting flux is not important for the dynamics of switchbacks.

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47

Sharma, S., P. Galav, N. Dashora, and R. Pandey. "Longitudinal study of the ionospheric response to the geomagnetic storm of 15 May 2005 and manifestation of TADs." Annales Geophysicae 29, no. 6 (June 17, 2011): 1063–70. http://dx.doi.org/10.5194/angeo-29-1063-2011.

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Abstract. Response of low latitude ionosphere to the geomagnetic storm of 15 May 2005 has been studied using total electron content (TEC) data, obtained from three GPS stations namely, Yibal, Udaipur and Kunming situated near the northern crest of equatorial ionization anomaly at different longitudes. Solar wind parameters, north-south component of the interplanetary magnetic field (IMF Bz) and AE index data have been used to infer the strength of the geomagnetic storm. A large value of eastward interplanetary electric field at 06:15 UT, during the time of maximum southward IMF Bz has been used to infer the transmission of an eastward prompt penetration electric field (PPEF) which resulted in a peak in TEC at 07:45 UT due to the local uplift of plasma in the low latitudes near the anomaly crest over a wide range of longitudes. Wave-like modulations superposed over the second enhancement in TEC between 09:15 UT to 10:30 UT have been observed at all the three stations. The second enhancement in TEC along with the modulations of up to 5 TECU have been attributed to the combined effect of super plasma fountain and traveling atmospheric disturbances (TAD). Observed large enhancements in TEC are a cause of concern for satellite based navigation and ground positioning. Increased [O/N2] ratio between 09:15 UT to 10:15 UT when modulations in TEC have been also observed, confirms the presence of TADs over a wide range of longitudes.

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48

Shulman, A. Ya. "Edge Condition in Diffraction Theory and Maximum Enhancement of Electromagnetic Field in the Near Zone." physica status solidi (a) 175, no. 1 (September 1999): 279–87. http://dx.doi.org/10.1002/(sici)1521-396x(199909)175:1<279::aid-pssa279>3.0.co;2-v.

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49

GINZBURG, N. S., YU V. NOVOZHILOVA, and N. YU. PESKOV. "THE THEORY OF FREE ELECTRON LASERS WITH AXIAL GUIDE MAGNETIC FIELD." International Journal of High Speed Electronics and Systems 04, no. 04 (December 1993): 315–48. http://dx.doi.org/10.1142/s0129156493000157.

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Amplification and generation schemes of free electron lasers with a helical undulator and homogeneous guiding magnetic field are considered. A description of the process of pumping bounce oscillations of electrons in the adiabatically tapered undulator field is presented. The electron beam interacts with the electromagnetic wave in the region of constant amplitude of the undulator field where electrons move along stationary helical trajectories. Linear and nonlinear theory of such interaction is developed when electrons are under the undulator and combined synchronism with the electromagnetic wave. In the latter case the radiation is accompanied by excitation of electron oscillations near the equilibrium trajectory. A range of parameters for undulator synchronism is found where a considerable Doppler frequency up-conversion can be realized simultaneously with high efficiency (for amplifiers more then 30%). The mechanism of efficiency enhancement in this region is described. The influence of HF space charge (including negative mass effects) and the transverse inhomogeneity of the undulator field is discussed.

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50

Kirk, T. L., L. G. De Pietro, D. Pescia, and U. Ramsperger. "Electron beam confinement and image contrast enhancement in near field emission scanning electron microscopy." Ultramicroscopy 109, no. 5 (April 2009): 463–66. http://dx.doi.org/10.1016/j.ultramic.2008.11.009.

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