1,511 results on '"Torbert, R. B."'
Search Results
102. Origin and structure of electromagnetic generator regions at the edge of the electron diffusion region
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Payne, D. S., primary, Farrugia, C. J., additional, Torbert, R. B., additional, Germaschewski, K., additional, Rogers, A. R., additional, and Argall, M. R., additional
- Published
- 2021
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103. The Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) on RBSP
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Kletzing, C. A., Kurth, W. S., Acuna, M., MacDowall, R. J., Torbert, R. B., Averkamp, T., Bodet, D., Bounds, S. R., Chutter, M., Connerney, J., Crawford, D., Dolan, J. S., Dvorsky, R., Hospodarsky, G. B., Howard, J., Jordanova, V., Johnson, R. A., Kirchner, D. L., Mokrzycki, B., Needell, G., Odom, J., Mark, D., Pfaff, Jr., R., Phillips, J. R., Piker, C. W., Remington, S. L., Rowland, D., Santolik, O., Schnurr, R., Sheppard, D., Smith, C. W., Thorne, R. M., and Tyler, J.
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- 2013
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104. Reconnection Guide Field and Quadrupolar Structure Observed by MMS on 16 October 2015 at 1307 UT
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Denton, R. E, Sonnerup, B. U. O, Hasagawa, H, Phan, T. D, Russell, C. T, Strangeway, R. J, Giles, B. L, and Torbert, R. B
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Space Sciences (General) - Abstract
We estimate the guide field near the X point, B(sub M0), for a magnetopause crossing by the Magnetospheric Multiscale (MMS) spacecraft at 1307 UT on 16 October 2015 that showed features of electron-scale reconnection. This component of the magnetic field is normal to the reconnection plane L-N containing the reconnection magnetic field, B(sub L), and the direction e(sub N) normal to the current sheet. The B(sub M) field component appears to approximately have quadrupolar structure close to the X point. Using several different methods to estimate values of the guide field near the X point, some of which use an assumed quadrupolar symmetry, we find values ranging between -3.1 nT and -1.2 nT, with a nominal value of about -2.5 nT. The rough consistency of these values is evidence that the quadrupolar structure exists.
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- 2016
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105. The Substructure of a Flux Transfer Event Observed by the MMS Spacecraft
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Hwang, K.-J, Sibeck, D. G, Giles, B. L, Pollock, C. J, Gershman, D, Avanov, L, Paterson, W. R, Dorelli, J. C, Ergun, R. E, Russel, C. T, Strangeway, R. J, Mauk, B, Cohen, I. J, Torbert, R. B, and Burch, J. L
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Geophysics - Abstract
On 15 August 2015, MMS (Magnetospheric Multiscale mission), skimming the dusk magnetopause, detected an isolated region of an increased magnetic strength and bipolar Bn, indicating a flux transfer event (FTE). The four spacecraft in a tetrahedron allowed for investigations of the shape and motion of the FTE. In particular, high-resolution particle data facilitated our exploration of FTE substructures and their magnetic connectivity inside and surrounding the FTE. Combined field and plasma observations suggest that the core fields are open, magnetically connected to the northern magnetosphere from which high-energy particles leak; ion "D" distributions characterize the axis of flux ropes that carry old-opened field lines; counter streaming electrons superposed by parallel-heated components populate the periphery surrounding the FTE; and the interface between the core and draped regions contains a separatrix of newlyopened magnetic field lines that emanate from the X line above the FTE.
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- 2016
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106. Stable Reconnection at the Dusk Flank Magnetopause
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Gomez, R. G, Vines, S. K, Fuselier, S. A, Cassak, P. A, Strangeway, R. J, Petrinec, S. M, Burch, J. L, Trattner, K. J, Russell, C. T, Torbert, R. B, and Pollock, C
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Geophysics - Abstract
The dusk flank magnetopause was surveyed with instruments on board the Magnetospheric Multiscale (MMS) spacecraft on 28 August 2015 between 13:55 UT and 14:15 UT during a period of persistent southward interplanetary magnetic field (IMF) with varying dawn-dusk component. Plasma measurements (500 eV electrons are greater than 2 keV ions) revealed the existence of at least one active reconnection region that persisted throughout the interval. The reconnection region convected equatorward despite the poleward and tailward magnetosheath flow, which ranged from slightly sub-Alfvenic to slightly super-Alfvenic throughout the interval. These results suggest that magnetic reconnection moved in response to changes in the IMF clock angle rather than the magnetosheath flow, which is corroborated using predictions of the maximum magnetic shear model.
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- 2016
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107. Observations of Large-Amplitude, Parallel, Electrostatic Waves Associated with the Kelvin-Helmholtz Instability by the Magnetospheric Multiscale Mission
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Wilder, F. D, Ergun, R. E, Schwartz, S. J, Newman, D. L, Eriksson, S, Stawarz, J. E, Goldman, M. V, Goodrich, K. A, Gershman, D. J, Malaspina, D, Holmes, J. C, Sturner, A. P, Burch, J. L, Torbert, R. B, Lindqvist, P.-A, Marklund, G. T, Khotyaintsev, Y, Strangeway, R. J, Russell, C. T, Pollock, C. J, Giles, B. L, Dorrelli, J. C, Avanov, L. A, Patterson, W. R, Plaschke, F, and Magnes, W
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Plasma Physics - Abstract
On 8 September 2015, the four Magnetospheric Multiscale spacecraft encountered a Kelvin-Helmholtz unstable magnetopause near the dusk flank. The spacecraft observed periodic compressed current sheets, between which the plasma was turbulent. We present observations of large-amplitude (up to 100 mVm) oscillations in the electric field. Because these oscillations are purely parallel to the background magnetic field, electrostatic, and below the ion plasma frequency, they are likely to be ion acoustic-like waves. These waves are observed in a turbulent plasma where multiple particle populations are intermittently mixed, including cold electrons with energies less than 10 eV. Stability analysis suggests a cold electron component is necessary for wave growth.
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- 2016
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108. On Electron-Scale Whistler Turbulence in the Solar Wind
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Narita, Y, Nakamura, R, Baumjohann, W, Glassmeier, K.-H, Motschmann, U, Giles, B, Magnes, W, Fischer, D, Torbert, R. B, and Russell, C. T
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Plasma Physics ,General - Abstract
For the first time, the dispersion relation for turbulence magnetic field fluctuations in the solar wind is determined directly on small scales of the order of the electron inertial length, using four-point magnetometer observations from the Magnetospheric Multiscale mission. The data are analyzed using the high-resolution adaptive wave telescope technique. Small-scale solar wind turbulence is primarily composed of highly obliquely propagating waves, with dispersion consistent with that of the whistler mode.
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- 2016
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109. Energy Limits of Electron Acceleration in the Plasma Sheet During Substorms: A Case Study with the Magnetospheric Multiscale (MMS) Mission
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Turner, D. L, Fennell, J. F, Blake, J. B, Clemmons, J. H, Mauk, B. H, Cohen, I. J, Jaynes, A. N, Craft, J. V, Wilder, F. D, Baker, D. N, Reeves, G. D, Gershman, D. J, Avanov, L. A, Dorelli, J. C, Giles, B. L, Pollock, T. C, Schmid, D, Nakamura, R, Strangeway, R. J, Russell, C. T, Artemyev, A. V, Runov, A, Angelopoulos, V, Spence, H. E, Torbert, R. B, and Burch, J. L
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Space Sciences (General) - Abstract
We present multipoint observations of earthward moving dipolarization fronts and energetic particle injections from NASAs Magnetospheric Multiscale mission with a focus on electron acceleration. From a case study during a substorm on 02 August 2015, we find that electrons are only accelerated over a finite energy range, from a lower energy threshold at approx. 7-9 keV up to an upper energy cutoff in the hundreds of keV range. At energies lower than the threshold energy, electron fluxes decrease, potentially due to precipitation by strong parallel electrostatic wavefields or initial sources in the lobes. Electrons at energies higher than the threshold are accelerated cumulatively by a series of impulsive magnetic dipolarization events. This case demonstrates how the upper energy cutoff increases, in this case from approx. 130 keV to >500 keV, with each depolarization/injection during sustained activity. We also present a simple model accounting for these energy limits that reveals that electron energization is dominated by betatron acceleration.
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- 2016
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110. Inverse Energy Dispersion of Energetic Ions Observed in the Magnetosheath
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Lee, S. H, Sibeck, D. G, Hwang, K.-J, Wang, Y, Silveira, M. V. D, Fok, M.-C, Mauk, B. H, Cohen, I. J, Ruohoniemi, J. M, Kitamura, N, Burch, J. L, Giles, B. L, Torbert, R. B, Russell, C. T, and Lester, M
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Space Sciences (General) - Abstract
We present a case study of energetic ions observed by the Energetic Particle Detector (EPD) on the Magnetospheric Multiscale spacecraft in the magnetosheath just outside the subsolar magnetopause that occurred at 1000 UT on 8 December 2015. As the magnetopause receded inward, the EPD observed a burst of energetic (approximately 50-1000 keV) proton, helium, and oxygen ions that exhibited an inverse dispersion, with the lowest energy ions appearing first. The prolonged interval of fast antisunward flow observed in the magnetosheath and transient increases in the H components of global ground magnetograms demonstrate that the burst appeared at a time when the magnetosphere was rapidly compressed. We attribute the inverse energy dispersion to the leakage along reconnected magnetic field lines of betatron-accelerated energetic ions in the magnetosheath, and a burst of reconnection has an extent of about 1.5 R(sub E) using combined Super Dual Auroral Radar Network radar and EPD observations.
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- 2016
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111. Magnetospheric Multiscale Observations of the Electron Diffusion Region of Large Guide Field Magnetic Reconnection
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Eriksson, S, Wilder, F. D, Ergun, R. E, Schwartz, S. J, Cassak, P. A, Burch, J. L, Chen, Li-Jen, Torbert, R. B, Phan, T. D, Lavraud, B, Pollock, C. J, Giles, B. L, and Hesse, M
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Geophysics - Abstract
We report observations from the Magnetospheric Multiscale (MMS) satellites of a large guide field magnetic reconnection event. The observations suggest that two of the four MMS spacecraft sampled the electron diffusion region, whereas the other two spacecraft detected the exhaust jet from the event. The guide magnetic field amplitude is approximately 4 times that of the reconnecting field. The event is accompanied by a significant parallel electric field (E(sub parallel lines) that is larger than predicted by simulations. The high-speed (approximately 300 km/s) crossing of the electron diffusion region limited the data set to one complete electron distribution inside of the electron diffusion region, which shows significant parallel heating. The data suggest that E(sub parallel lines) is balanced by a combination of electron inertia and a parallel gradient of the gyrotropic electron pressure.
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- 2016
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112. Magnetospheric Multiscale Mission Observations and Non-Force Free Modeling of a Flux Transfer Event Immersed in a Super-Alfvenic Flow
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Farrugia, C. J, Lavraud, B, Torbert, R. B, Argall, M, Kacem, I, Yu, W, Alm, L, Burch, J, Russell, C. T, Shuster, J, Dorelli, J, Giles, B. L, and Pollock, C
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Geophysics - Abstract
We analyze plasma, magnetic field, and electric field data for a flux transfer event (FTE) to highlight improvements in our understanding of these transient reconnection signatures resulting from high-resolution data. The approximate 20 s long, reverse FTE, which occurred south of the geomagnetic equator near dusk, was immersed in super-Alfvnic flow. The field line twist is illustrated by the behavior of flows parallel perpendicular to the magnetic field. Four-spacecraft timing and energetic particle pitch angle anisotropies indicate a flux rope (FR) connected to the Northern Hemisphere and moving southeast. The flow forces evidently overcame the magnetic tension. The high-speed flows inside the FR were different from those outside. The external flows were perpendicular to the field as expected for draping of the external field around the FR. Modeling the FR analytically, we adopt a non-force free approach since the current perpendicular to the field is nonzero. It reproduces many features of the observations.
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- 2016
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113. Observations of Energetic Particle Escape at the Magnetopause: Early Results from the MMS Energetic Ion Spectrometer (EIS)
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Cohen, I. J, Mauk, B. H, Anderson, B. J, Westlake, J. H, Sibeck, David Gary, Giles, Barbara L, Pollock, C. J, Turner, D. L, Fennell, J. F, Blake, J. B, Clemmons, J. H, Jaynes, A. N, Baker, D. N, Craft, J. V, Spence, H. E, Niehof, J. T, Reeves, G. D, Torbert, R. B, Russell, C. T, Strangeway, R. J, Magnes, W, Trattner, K. J, Fuselier, S. A, and Burch, J. L
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Space Sciences (General) - Abstract
Energetic (greater than tens of keV) magnetospheric particle escape into the magnetosheath occurs commonly, irrespective of conditions that engender reconnection and boundary-normal magnetic fields. A signature observed by the Magnetospheric Multiscale (MMS) mission, simultaneous monohemispheric streaming of multiple species (electrons, H+, Hen+), is reported here as unexpectedly common in the dayside, dusk quadrant of the magnetosheath even though that region is thought to be drift-shadowed from energetic electrons. This signature is sometimes part of a pitch angle distribution evolving from symmetric in the magnetosphere, to asymmetric approaching the magnetopause, to monohemispheric streaming in the magnetosheath. While monohemispheric streaming in the magnetosheath may be possible without a boundary-normal magnetic field, the additional pitch angle depletion, particularly of electrons, on the magnetospheric side requires one. Observations of this signature in the dayside dusk sector imply that the static picture of magnetospheric drift-shadowing is inappropriate for energetic particle dynamics in the outer magnetosphere.
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- 2016
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114. Estimates of Terms in Ohm's Law During an Encounter with an Electron Diffusion Region
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Torbert, R. B, Burch, J. L, Giles, B. L, Gershman, D, Pollock, C. J, Dorelli, J, Avanov, L. A, Argall, M, Shuster, J, Strangeway, R, and Moore, T. E
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General - Abstract
We present measurements from the Magnetospheric Multiscale (MMS) mission taken during a reconnection event on the dayside magnetopause which includes a passage through an electron diffusion region (EDR). The four MMS satellites were separated by about 10 km such that estimates of gradients and divergences allow a reasonable estimate of terms in the generalized Ohm's law, which is key to investigating the energy dissipation during reconnection. The strength and character of dissipation mechanisms determines how magnetic energy is released. We show that both electron pressure gradients and electron inertial effects are important, but not the only participants in reconnection near EDRs, since there are residuals of a few mVm (approximately 30-50%) of E+ U(sub e) x B (from the sum of these two terms) during the encounters. These results are compared to a simulation, which exhibits many of the observed features, but where relatively little residual is present.
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- 2016
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115. Magnetospheric Multiscale Satellites Observations of Parallel Electric Fields Associated with Magnetic Reconnection
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Ergun, R. E, Goodrich, K. A, Wilder, F. D, Holmes, J. C, Stawarz, J. E, Eriksson, S, Sturner, A. P, Malaspina, D. M, Usanova, M. E, Torbert, R. B, Lindqvist, P.-A, Khotyaintsev, Y, Burch, J. L, Strangeway, R. J, Russell, C. T, Pollock, C. J, Giles, B. L, Hesse, M, Chen, L. J, Lapenta, G, Goldman, M. V, Newman, D. L, Schwartz, S. J, Eastwood, J. P, Phan, T. D, Mozer, F. S, Drake, J, Shay, M. A, Cassak, P. A, Nakamura, R, and Marklund, G
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Geophysics - Abstract
We report observations from the Magnetospheric Multiscale satellites of parallel electric fields (E (sub parallel)) associated with magnetic reconnection in the subsolar region of the Earth's magnetopause. E (sub parallel) events near the electron diffusion region have amplitudes on the order of 100 millivolts per meter, which are significantly larger than those predicted for an antiparallel reconnection electric field. This Letter addresses specific types of E (sub parallel) events, which appear as large-amplitude, near unipolar spikes that are associated with tangled, reconnected magnetic fields. These E (sub parallel) events are primarily in or near a current layer near the separatrix and are interpreted to be double layers that may be responsible for secondary reconnection in tangled magnetic fields or flux ropes. These results are telling of the three-dimensional nature of magnetopause reconnection and indicate that magnetopause reconnection may be often patchy and/or drive turbulence along the separatrix that results in flux ropes and/or tangled magnetic fields.
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- 2016
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116. Shift of the Magnetopause Reconnection Line to the Winter Hemisphere Under Southward IMF Conditions: Geotail and MMS Observations
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Kitamura, N, Hasegawa, H, Saito, Y, Shinohara, I, Yokota, S, Nagai, T, Pollock, C. J, Giles, B. L, Moore, T. E, Dorelli, J. C, Gershman, D. J, Avanov, L. A, Paterson, W. R, Coffey, V. N, Chandler, M. O, Sauvaud, J. A, Lavraud, B, Torbert, R. B, Russell, C. T, Strangeway, R. J, and Burch, J. L
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Astrophysics - Abstract
At 02:13 UT on 18 November 2015 when the geomagnetic dipole was tilted by -27deg, the MMS spacecraft observed southward reconnection jets near the subsolar magnetopause under southward and dawnward interplanetary magnetic field conditions. Based on four-spacecraft estimations of the magnetic field direction near the separatrix and the motion and direction of the current sheet, the location of the reconnection line was estimated to be approx.1.8 R(sub E) or further northward of MMS. The Geotail spacecraft at GSM Z approx. 1.4 R(sub E) also observed southward reconnection jets at the dawnside magnetopause 30-40 min later. The estimated reconnection line location was northward of GSM Z approx.2 R(sub E). This crossing occurred when MMS observed purely southward magnetic fields in the magnetosheath. The simultaneous observations are thus consistent with the hypothesis that the dayside magnetopause reconnection line shifts from the subsolar point toward the northem (winter) hemisphere due to the effect of geomagnetic dipole tilt.
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- 2016
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117. Motion of the MMS Spacecraft Relative to the Magnetic Reconnection Structure Observed on 16 October 2015 at 1307 UT
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Denton, R. E, Sonnerup, B. U. O, Hasegawa, H, Phan, T. D, Russell, C. T, Strangeway, R, Giles, B. L, Gershman, D, and Torbert, R. B
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Geophysics ,Numerical Analysis - Abstract
We analyze a magnetopause crossing by the Magnetospheric Multiscale (MMS) spacecraft at 1307 UT on 16 October 2016 that showed features of electron-scale reconnection. For this event, we find orthonormal LMN coordinates from the magnetic field, with N and L varying respectively along the maximum gradient and maximum variance directions. We find the motion along N from the Spatio-Temporal Difference analysis and motion along L from measured particle velocities. We locate the position of the magnetic X point, finding that MMS-4 passed within about 1A km from the X point and that MMS-3 and MMS-2 passed within about 1.7 km and 2.4 km, respectively, from the position of maximum out of plane current.
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- 2016
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118. Study of the Spacecraft Potential Under Active Control and Plasma Density Estimates During the MMS Commissioning Phase
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Andriopoulou, M, Nakamura, R, Torkar, K, Baumjohann, W, Torbert, R. B, Lindqvist, P.-A, Khotyaintsev, Y. V, Dorelli, John Charles, Burch, J. L, and Russell, C. T
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Plasma Physics ,Instrumentation And Photography - Abstract
Each spacecraft of the recently launched magnetospheric multiscale MMS mission is equipped with Active Spacecraft Potential Control (ASPOC) Instruments, which control the spacecraft potential in order to reduce spacecraft charging effects. ASPOC typically reduces the spacecraft potential to a few volts. On several occasions during the commissioning phase of the mission, the ASPOC instruments were operating only on one spacecraft at a time. Taking advantage of such intervals, we derive photoelectron curves and also perform reconstructions of the uncontrolled spacecraft potential for the spacecraft with active control and estimate the electron plasma density during those periods. We also establish the criteria under which our methods can be applied.
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- 2016
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119. Transient, Small-Scale Field-Aligned Currents in the Plasma Sheet Boundary Layer During Storm Time Substorms
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Nakamura, R, Sergeev, V. A, Baumjohann, W, Plaschke, F, Magnes, W, Fischer, D, Varsani, A, Schmid, D, Nakamura, T. K. M, Russell, C. T, Strangeway, R. J, Leinweber, H. K, Le, G, Bromund, K. R, Pollock, C. J, Giles, B. L, Dorelli, J. C, Gershman, D. J, Paterson, W, Avanov, L. A, Fuselier, S. A, Genestreti, K, Burch, J. L, Torbert, R. B, Chutter, M, Argall, M. R, Anderson, B. J, Lindqvist, P.-A, Marklund, G. T, Khotyaintsev, Y. V, Mauk, B. H, Cohen, I. J, Baker, D. N, Jaynes, A. N, Ergun, R. E, Kepko, E. L, Moore, T. E, and Coffey, V
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Geophysics - Abstract
We report on field-aligned current observations by the four Magnetospheric Multiscale (MMS) spacecraft near the plasma sheet boundary layer (PSBL) during two major substorms on 23 June 2015. Small-scale field-aligned currents were found embedded in fluctuating PSBL flux tubes near the Separatrix region. We resolve, for the first time, short-lived earthward (downward) intense field-aligned current sheets with thicknesses of a few tens of kilometers, which are well below the ion scale, on flux tubes moving equatorward earth ward during outward plasma sheet expansion. They coincide with upward field-aligned electron beams with energies of a few hundred eV. These electrons are most likely due to acceleration associated with a reconnection jet or high-energy ion beam-produced disturbances. The observations highlight coupling of multiscale processes in PSBL as a consequence of magnetotail reconnection.
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- 2016
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120. Wave Telescope Technique for MMS Magnetometer
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Narita, Y, Plaschke, F, Nakamura, R, Baumjojann, W, Magnes, W, Fischer, D, Voros, Z, Torbert, R. B, Russell, C. T, Strangeway, R. J, Bromund, K. R, Le, G, and Kepko, E. L
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Astronomy ,Astrophysics - Abstract
Multipoint measurements are a powerful method in studying wavefields in space plasmas.The wave telescope technique is tested against magnetic field fluctuations in the terrestrial magnetosheath measured by the four Magnetospheric Multiscale (MMS) spacecraft on a spatial scale of about 20 km.The dispersion relation diagram and the wave vector distribution are determined for the first time in the ion-kinetic range. Moreover, the dispersion relation diagram is determined in a proxy plasma restframe by regarding the low-frequency dispersion relation as a Doppler relation and compensating for the apparent phase velocity. Fluctuations are highly compressible, and the wave vectors have an angle of about 60 from the mean magnetic field. We interpret that the measured fluctuations represent akinetic-drift mirror mode in the magnetosheath which is dispersive and in a turbulent state accompanied by a sideband formation.
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- 2016
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121. Magnetospheric Multiscale Satellite Observations of Parallel Electron Acceleration in Magnetic Field Reconnection by Fermi Reflection from Time Domain Structures
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Mozer, F. S, Agapitov, O. A, Artemyev, A, Burch, J. L, Ergun, R. E, Giles, B. L, Mourenas, D, Torbert, R. B, Phan, T. D, and Vasko, I
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Numerical Analysis ,Geophysics - Abstract
The same time domain structures (TDS) have been observed on two Magnetospheric Multiscale Satellites near Earth's dayside magnetopause. These TDS, traveling away from the X line along the magnetic field at 4000 km/s, accelerated field-aligned approx. 5 eV electrons to approx. 200 eV by a single Fermi reflection of the electrons by these overtaking barriers. Additionally, the TDS contained both positive and negative potentials, so they were a mixture of electron holes and double layers. They evolve in approx.10 km of space or 7 ms of time and their spatial scale size is 10-20 km, which is much larger than the electron gyroradius (less than1km) or the electron inertial length (4 km at the observation point, less nearer the X line).
- Published
- 2016
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122. In-Flight Calibration Processes for the MMS Fluxgate Magnetometers
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Bromund, K. R, Leinweber, H. K, Plaschke, F, Strangeway, R. J, Magnes, W, Fischer, D, Nakamura, R, Anderson, B. J, Russell, C. T, Baumjohann, W, Chutter, M, Torbert, R. B, Le, G, Slavin, J. A, and Kepko, E. L
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Instrumentation And Photography - Abstract
The calibration effort for the Magnetospheric Multiscale Mission (MMS) Analog Fluxgate (AFG) and DigitalFluxgate (DFG) magnetometers is a coordinated effort between three primary institutions: University of California, LosAngeles (UCLA); Space Research Institute, Graz, Austria (IWF); and Goddard Space Flight Center (GSFC). Since thesuccessful deployment of all 8 magnetometers on 17 March 2015, the effort to confirm and update the groundcalibrations has been underway during the MMS commissioning phase. The in-flight calibration processes evaluatetwelve parameters that determine the alignment, orthogonalization, offsets, and gains for all 8 magnetometers usingalgorithms originally developed by UCLA and the Technical University of Braunschweig and tailored to MMS by IWF,UCLA, and GSFC. We focus on the processes run at GSFC to determine the eight parameters associated with spin tonesand harmonics. We will also discuss the processing flow and interchange of parameters between GSFC, IWF, and UCLA.IWF determines the low range spin axis offsets using the Electron Drift Instrument (EDI). UCLA determines the absolutegains and sensor azimuth orientation using Earth field comparisons. We evaluate the performance achieved for MMS andgive examples of the quality of the resulting calibrations.
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- 2015
123. The Occurrence and Prevalence of Time Domain Structures in the Kelvin-Helmholtz Instability at Different Positions Along the Earth’s Magnetospheric Flanks
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Wilder, F. D., primary, Ergun, R. E., additional, Gove, D., additional, Eriksson, S., additional, Hansel, P., additional, Ahmadi, N., additional, Malaspina, D. M., additional, Burch, J. L., additional, Torbert, R. B., additional, Strangeway, R. J., additional, and Giles, B. L., additional
- Published
- 2021
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124. Thin Current Sheet Behind the Dipolarization Front
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Nakamura, R., primary, Baumjohann, W., additional, Nakamura, T. K. M., additional, Panov, E. V., additional, Schmid, D., additional, Varsani, A., additional, Apatenkov, S., additional, Sergeev, V. A., additional, Birn, J., additional, Nagai, T., additional, Gabrielse, C., additional, André, M., additional, Burch, J. L., additional, Carr, C., additional, Dandouras, I. S., additional, Escoubet, C. P., additional, Fazakerley, A. N., additional, Giles, B. L., additional, Le Contel, O., additional, Russell, C. T., additional, and Torbert, R. B., additional
- Published
- 2021
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125. Upper‐Hybrid Waves Driven by Meandering Electrons Around Magnetic Reconnection X Line
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Li, W.‐Y., primary, Khotyaintsev, Yu V., additional, Tang, B.‐B., additional, Graham, D. B., additional, Norgren, C., additional, Vaivads, A., additional, André, M., additional, Le, A., additional, Egedal, J., additional, Dokgo, K., additional, Fujimoto, K., additional, He, J.‐S., additional, Burch, J. L., additional, Lindqvist, P.‐A., additional, Ergun, R. E., additional, Torbert, R. B., additional, Le Contel, O., additional, Gershman, D. J., additional, Giles, B. L., additional, Lavraud, B., additional, Fuselier, S., additional, Plaschke, F., additional, Russell, C. T., additional, Guo, X.‐C., additional, Lu, Q.‐M., additional, and Wang, C., additional
- Published
- 2021
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126. Reconnection With Magnetic Flux Pileup at the Interface of Converging Jets at the Magnetopause
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Oieroset, M., Phan, T. D., Drake, J. F., Eastwood, J. P., Fuselier, S. A., Strangeway, R. J., Haggerty, C., Shay, M. A., Wang, S., Chen, L.‐J., Kacem, I., Lavraud, B., Angelopoulos, V., Burch, J. L., Torbert, R. B., Ergun, R. E., Khotyaintsev, Y., Lindqvist, P. A., Gershman, D. J., Giles, B. L., Pollock, C., Moore, T. E., Russell, C. T., Avanov, L. A., Paterson, W., Oka, Mitsuo, Saito, Yoshifumi, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Science and Technology Facilities Council (STFC)
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010504 meteorology & atmospheric sciences ,Field (physics) ,Astrophysics::High Energy Astrophysical Phenomena ,Flux ,SHEAR EVIDENCE ,010502 geochemistry & geophysics ,01 natural sciences ,PLASMA BETA ,Current sheet ,DEPENDENCE ,Physics::Plasma Physics ,MD Multidisciplinary ,TOPOLOGY ,Meteorology & Atmospheric Sciences ,Astrophysics::Solar and Stellar Astrophysics ,Geosciences, Multidisciplinary ,FIELD ,0105 earth and related environmental sciences ,Science & Technology ,Geology ,Magnetic flux ,Computational physics ,MMS OBSERVATIONS ,Geophysics ,[SDU]Sciences of the Universe [physics] ,Physical Sciences ,Physics::Space Physics ,General Earth and Planetary Sciences ,Magnetopause - Abstract
著者人数: 27名, Accepted: 2019-01-15, 資料番号: SA1180269000
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- 2019
127. Reconstruction of the Electron Diffusion Region of Magnetotail Reconnection Seen by the MMS Spacecraft on 11 July 2017
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Denton, R. E., Nakamura, R., Genestreti, K. J., Hwang, K.‐J., Phan, T. D., Torbert, R. B., Burch, J. L., Giles, B. L., Gershman, D. J., Russell, C. T., Strangeway, R. J., Lindqvist, P.‐A., Khotyaintsev, Y. V., Ergun, R. E., Hasegawa, Hiroshi, Nakamura, T. K. M., Kitamura, Naritoshi, and Saito, Yoshifumi
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Physics ,Geophysics ,Spacecraft ,Space and Planetary Science ,business.industry ,Event (relativity) ,Physics::Space Physics ,Magnetic reconnection ,Electron ,Diffusion (business) ,business ,Computational physics - Abstract
著者人数: 18名, Accepted: 2018-11-03, 資料番号: SA1180295000
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- 2019
128. Measurement of the Magnetic Reconnection Rate in the Earth's Magnetotail
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Genestreti, K. J., Liu, Y.‐H., Nakamura, R., Teh, W.‐L., Daughton, W., Hesse, M., Torbert, R. B., Burch, J. L., Giles, B. L., Nakamura, T. K. M., and Hasegawa, Hiroshi
- Abstract
著者人数: 11名, Accepted: 2018-09-11, 資料番号: SA1180290000
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- 2018
129. Deep Solar Activity Minimum 2007 – 2009: Solar Wind Properties and Major Effects on the Terrestrial Magnetosphere
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Farrugia, C. J., Harris, B., Leitner, M., Möstl, C., Galvin, A. B., Simunac, K. D. C., Torbert, R. B., Temmer, M. B., Veronig, A. M., Erkaev, N. V., Szabo, A., Ogilvie, K. W., Luhmann, J. G., and Osherovich, V. A.
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- 2012
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130. Magnetospheric Multiscale Overview and Science Objectives
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Burch, J. L, Moore, T. E, Torbert, R. B, and Giles, B. L
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Astrophysics - Abstract
Magnetospheric Multiscale (MMS), a NASA four-spacecraft constellation mission launched on March 12, 2015, will investigate magnetic reconnection in the boundary regions of the Earth's magnetosphere, particularly along its dayside boundary with the solar wind and the neutral sheet in the magnetic tail. The most important goal of MMS is to conduct a definitive experiment to determine what causes magnetic field lines to reconnect in a collisionless plasma. The significance of the MMS results will extend far beyond the Earth's magnetosphere because reconnection is known to occur in interplanetary space and in the solar corona where it is responsible for solar flares and the disconnection events known as coronal mass ejections. Active research is also being conducted on reconnection in the laboratory and specifically in magnetic-confinement fusion devices in which it is a limiting factor in achieving and maintaining electron temperatures high enough to initiate fusion. Finally, reconnection is proposed as the cause of numerous phenomena throughout the universe such as comet-tail disconnection events, magnetar flares, supernova ejections, and dynamics of neutron-star accretion disks. The MMS mission design is focused on answering specific questions about reconnection at the Earth's magnetosphere. The prime focus of the mission is on determining the kinetic processes occurring in the electron diffusion region that are responsible for reconnection and that determine how it is initiated; but the mission will also place that physics into the context of the broad spectrum of physical processes associated with reconnection. Connections to other disciplines such as solar physics, astrophysics, and laboratory plasma physics are expected to be made through theory and modeling as informed by the MMS results.
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- 2015
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131. Comparison of MMS Observations of Foreshock Bubbles With a Global Hybrid Simulation
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Lee, S. H., primary, Sibeck, D. G., additional, Omidi, N., additional, Silveira, M. V. D., additional, Giles, B. L., additional, Torbert, R. B., additional, Russell, C. T., additional, Wei, H., additional, and Burch, J. L., additional
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- 2021
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132. Microscale Processes Determining Macroscale Evolution of Magnetic Flux Tubes along Earth’s Magnetopause
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Hwang, K.-J., primary, Burch, J. L., additional, Russell, C. T., additional, Choi, E., additional, Dokgo, K., additional, Fear, R. C., additional, Fuselier, S. A., additional, Petrinec, S. M., additional, Sibeck, D. G., additional, Hasegawa, H., additional, Fu, H., additional, Øieroset, M., additional, Escoubet, C. P., additional, Giles, B. L., additional, Khotyaintsev, Y., additional, Graham, D. B., additional, Gershman, D. J., additional, Pollock, C. J., additional, Ergun, R. E., additional, Torbert, R. B., additional, and Broll, J., additional
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- 2021
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133. Results of the Electron Drift Instrument on Cluster
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Paschmann, G., primary, Quinn, J. M., additional, Torbert, R. B., additional, McIlwain, C. E., additional, Vaith, H., additional, Haaland, S., additional, Matsui, H., additional, Kletzing, C. A., additional, Baumjohann, W., additional, and Haerendel, G., additional
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- 2021
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134. A Multi‐Instrument Study of a Dipolarization Event in the Inner Magnetosphere
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Matsui, H., primary, Torbert, R. B., additional, Spence, H. E., additional, Argall, M. R., additional, Cohen, I. J., additional, Cooper, M. B., additional, Ergun, R. E., additional, Farrugia, C. J., additional, Fennell, J. F., additional, Fuselier, S. A., additional, Gkioulidou, M., additional, Khotyaintsev, Yu. V., additional, Lindqvist, P.‐A., additional, Matsuoka, A., additional, Russell, C. T., additional, Shoji, M., additional, Strangeway, R. J., additional, Turner, D. L., additional, Vaith, H., additional, and Wygant, J. R., additional
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- 2021
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135. Origin of Electron‐Scale Magnetic Fluctuations Close to an Electron Diffusion Region
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Hoilijoki, S., primary, Pucci, F., additional, Ergun, R. E., additional, Schwartz, S. J., additional, Wilder, F. D., additional, Eriksson, S., additional, Chasapis, A., additional, Ahmadi, N., additional, Webster, J. M., additional, Burch, J. L., additional, Torbert, R. B., additional, Strangeway, R. J., additional, and Giles, B. L., additional
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- 2021
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136. The FIELDS Instrument Suite on MMS: Scientific Objectives, Measurements, and Data Products
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Torbert, R. B, Russell, C. T, Magnes, W, Ergun, R. E, Lindqvist, P.-A, LeContel, O, Vaith, H, Macri, J, Myers, S, Rau, D, Needell, J, King, B, Granoff, M, Chutter, M, Dors, I, Olsson, G, Khotyaintsev, Y. V, Eriksson, A, Kletzing, C. A, Bounds, S, Anderson, B, Baumjohann, W, Steller, M, Bromund, K, Le, Guan, Nakamura, R, Strangeway, R. J, Leinweber, H. K, Tucker, S, Westfall, J, Fischer, D, Plaschke, F, Porter, J, and Lappalainen, K
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Space Radiation ,Astrophysics - Abstract
The FIELDS instrumentation suite on the Magnetospheric Multiscale (MMS) mission provides comprehensive measurements of the full vector magnetic and electric fields in the reconnection regions investigated by MMS, including the dayside magnetopause and the night-side magnetotail acceleration regions out to 25 Re. Six sensors on each of the four MMS spacecraft provide overlapping measurements of these fields with sensitive cross-calibrations both before and after launch. The FIELDS magnetic sensors consist of redundant flux-gate magnetometers (AFG and DFG) over the frequency range from DC to 64 Hz, a search coil magnetometer (SCM) providing AC measurements over the full whistler mode spectrum expected to be seen on MMS, and an Electron Drift Instrument (EDI) that calibrates offsets for the magnetometers. The FIELDS three-axis electric field measurements are provided by two sets of biased double-probe sensors (SDP and ADP) operating in a highly symmetric spacecraft environment to reduce significantly electrostatic errors. These sensors are complemented with the EDI electric measurements that are free from all local spacecraft perturbations. Cross-calibrated vector electric field measurements are thus produced from DC to 100 kHz, well beyond the upper hybrid resonance whose frequency provides an accurate determination of the local electron density. Due to its very large geometric factor, EDI also provides very high time resolution (∼1 ms) ambient electron flux measurements at a few selected energies near 1 keV. This paper provides an overview of the FIELDS suite, its science objectives and measurement requirements, and its performance as verified in calibration and cross-calibration procedures that result in anticipated errors less than 0.1 nT in B and 0.5 mV/m in E. Summaries of data products that result from FIELDS are also described, as well as algorithms for cross-calibration. Details of the design and performance characteristics of AFG/DFG, SCM, ADP, SDP, and EDI are provided in five companion papers.
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- 2014
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137. Bifurcated Current Sheet Observed on the Boundary of Kelvin-Helmholtz Vortices
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Hwang, K.-J., Dokgo, K., Choi, E., Burch, J. L., Sibeck, D. G., Giles, B. L., Norgren, C., Nakamura, T. K. M., Graham, Daniel B., Khotyaintsev, Yuri, Shi, Q. Q., Gershman, D. J., Pollock, C. J., Ergun, R. E., Torbert, R. B., Russell, C. T., and Strangeway, R. J.
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Astronomi, astrofysik och kosmologi ,magnetic reconnection ,Physics::Space Physics ,magnetopause ,Astronomy, Astrophysics and Cosmology ,Kelvin-Helmholtz vortex ,bifurcated current sheet ,Kelvin-Helmholtz wave - Abstract
On May 5, 2017 MMS observed a bifurcated current sheet at the boundary of Kelvin-Helmholtz vortices (KHVs) developed on the dawnside tailward magnetopause. We use the event to enhance our understanding of the formation and structure of asymmetric current sheets in the presence of density asymmetry, flow shear, and guide field, which have been rarely studied. The entire current layer comprises three separate current sheets, each corresponding to magnetosphere-side sunward separatrix region, central near-X-line region, and magnetosheath-side tailward separatrix region. Two off-center structures are identified as slow-mode discontinuities. All three current sheets have a thickness of ∼0.2 ion inertial length, demonstrating the sub-ion-scale current layer, where electrons mainly carry the current. We find that both the diamagnetic and electron anisotropy currents substantially support the bifurcated currents in the presence of density asymmetry and weak velocity shear. The combined effects of strong guide field, low density asymmetry, and weak flow shear appear to lead to asymmetries in the streamlines and the current-layer structure of the quadrupolar reconnection geometry. We also investigate intense electrostatics waves observed on the magnetosheath side of the KHV boundary. These waves may pre-heat a magnetosheath population that is to participate into the reconnection process, leading to two-step energization of the magnetosheath plasma entering into the magnetosphere via KHV-driven reconnection. publishedVersion
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- 2021
138. Thin Current Sheet Behind the Dipolarization Front
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Nakamura, R., Baumjohann, W., Nakamura, T. K. M., Panov, E. , V, Schmid, D., Varsani, A., Apatenkov, S., Sergeev, V. A., Birn, J., Nagai, T., Gabrielse, C., André, Mats, Burch, J. L., Carr, C., Dandouras, I. S., Escoubet, C. P., Fazakerley, A. N., Giles, B. L., Le Contel, O., Russell, C. T., Torbert, R. B., Nakamura, R., Baumjohann, W., Nakamura, T. K. M., Panov, E. , V, Schmid, D., Varsani, A., Apatenkov, S., Sergeev, V. A., Birn, J., Nagai, T., Gabrielse, C., André, Mats, Burch, J. L., Carr, C., Dandouras, I. S., Escoubet, C. P., Fazakerley, A. N., Giles, B. L., Le Contel, O., Russell, C. T., and Torbert, R. B.
- Abstract
We report a unique conjugate observation of fast flows and associated current sheet disturbances in the near-Earth magnetotail by MMS (Magnetospheric Multiscale) and Cluster preceding a positive bay onset of a small substorm at similar to 14:10 UT, September 8, 2018. MMS and Cluster were located both at X similar to -14 R-E. A dipolarization front (DF) of a localized fast flow was detected by Cluster and MMS, separated in the dawn-dusk direction by similar to 4 R-E,R- almost simultaneously. Adiabatic electron acceleration signatures revealed from the comparison of the energy spectra confirm that both spacecraft encounter the same DF. We analyzed the change in the current sheet structure based on multi-scale multi-point data analysis. The current sheet thickened during the passage of DF, yet, temporally thinned subsequently associated with another flow enhancement centered more on the dawnward side of the initial flow. MMS and Cluster observed intense perpendicular and parallel current in the off-equatorial region mainly during this interval of the current sheet thinning. Maximum field-aligned currents both at MMS and Cluster are directed tailward. Detailed analysis of MMS data showed that the intense field-aligned currents consisted of multiple small-scale intense current layers accompanied by enhanced Hall-currents in the dawn-dusk flow-shear region. We suggest that the current sheet thinning is related to the flow bouncing process and/or to the expansion/activation of reconnection. Based on these mesoscale and small-scale multipoint observations, 3D evolution of the flow and current-sheet disturbances was inferred preceding the development of a substorm current wedge.
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- 2021
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139. Spatial evolution of magnetic reconnection diffusion region structures with distance from the X-line
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Oieroset, M., Phan, T. D., Ergun, R., Ahmadi, N., Genestreti, K., Drake, J. F., Liu, Y-H, Haggerty, C., Eastwood, J. P., Shay, M. A., Pyakurel, P. S., Haaland, S., Oka, M., Goodbred, M., Eriksson, S., Burch, J. L., Torbert, R. B., Khotyaintsev, Yuri V., Russell, C. T., Strangeway, R. J., Gershman, D. J., Giles, B. L., Oieroset, M., Phan, T. D., Ergun, R., Ahmadi, N., Genestreti, K., Drake, J. F., Liu, Y-H, Haggerty, C., Eastwood, J. P., Shay, M. A., Pyakurel, P. S., Haaland, S., Oka, M., Goodbred, M., Eriksson, S., Burch, J. L., Torbert, R. B., Khotyaintsev, Yuri V., Russell, C. T., Strangeway, R. J., Gershman, D. J., and Giles, B. L.
- Abstract
We report Magnetospheric Multiscale four-spacecraft observations of a thin reconnecting current sheet with weakly asymmetric inflow conditions and a guide field of approximately twice the reconnecting magnetic field. The event was observed at the interface of interlinked magnetic field lines at the flank magnetopause when the maximum spacecraft separation was 370 km and the spacecraft covered & SIM;1.7 ion inertial lengths (d(i)) in the reconnection outflow direction. The ion-scale spacecraft separation made it possible to observe the transition from electron-only super ion-Alfvenic outflow near the electron diffusion region (EDR) to the emergence of sub-Alfvenic ion outflow in the ion diffusion region (IDR). The EDR to IDR evolution over a distance less than 2 d(i) also shows the transition from a near-linear reconnecting magnetic field reversal to a more bifurcated current sheet as well as significant decreases in the parallel electric field and dissipation. Both the ion and electron heating in this diffusion region event were similar to the previously reported heating in the far downstream exhausts. The dimensionless reconnection rate, obtained four different ways, was in the range of 0.13-0.27. This event reveals the rapid spatial evolution of the plasma and electromagnetic fields through the EDR to IDR transition region.& nbsp;(C) 2021 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
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- 2021
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140. Low-frequency Whistler Waves Modulate Electrons and Generate Higher-frequency Whistler Waves in the Solar Wind
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Yao, S. T., Shi, Q. Q., Zong, Q. G., Degeling, A. W., Guo, R. L., Li, L., Li, J. X., Tian, A. M., Zhang, H., Yao, Z. H., Fu, H. S., Liu, C. M., Sun, W. J., Niu, Z., Li, W. Y., Liu, Z. Y., Le Contel, O., Zhang, S., Xiao, C., Shang, W. S., Torbert, R. B., Ergun, R. E., Lindqvist, Per-Arne, Pollock, C. J., Yao, S. T., Shi, Q. Q., Zong, Q. G., Degeling, A. W., Guo, R. L., Li, L., Li, J. X., Tian, A. M., Zhang, H., Yao, Z. H., Fu, H. S., Liu, C. M., Sun, W. J., Niu, Z., Li, W. Y., Liu, Z. Y., Le Contel, O., Zhang, S., Xiao, C., Shang, W. S., Torbert, R. B., Ergun, R. E., Lindqvist, Per-Arne, and Pollock, C. J.
- Abstract
The role of whistler-mode waves in the solar wind and the relationship between their electromagnetic fields and charged particles is a fundamental question in space physics. Using high-temporal-resolution electromagnetic field and plasma data from the Magnetospheric MultiScale spacecraft, we report observations of low-frequency whistler waves and associated electromagnetic fields and particle behavior in the Earth's foreshock. The frequency of these whistler waves is close to half the lower-hybrid frequency (similar to 2 Hz), with their wavelength close to the ion gyroradius. The electron bulk flows are strongly modulated by these waves, with a modulation amplitude comparable to the solar wind velocity. At such a spatial scale, the electron flows are forcibly separated from the ion flows by the waves, resulting in strong electric currents and anisotropic ion distributions. Furthermore, we find that the low-frequency whistler wave propagates obliquely to the background magnetic field ( B (0)), and results in spatially periodic magnetic gradients in the direction parallel to B (0). Under such conditions, large pitch-angle electrons are trapped in wave magnetic valleys by the magnetic mirror force, and may provide free perpendicular electron energy to excite higher-frequency whistler waves. This study offers important clues and new insights into wave-particle interactions, wave generation, and microscale energy conversion processes in the solar wind., QC 20220110
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- 2021
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141. Upper-Hybrid Waves Driven by Meandering Electrons Around Magnetic Reconnection X Line
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Li, Wenya, Khotyaintsev, Yuri V., Tang, B-B, Graham, Daniel B., Norgren, C., Vaivads, A., André, Mats, Le, A., Egedal, J., Dokgo, K., Fujimoto, K., He, J-S, Burch, J. L., Lindqvist, P-A, Ergun, R. E., Torbert, R. B., Le Contel, O., Gershman, D. J., Giles, B. L., Lavraud, B., Fuselier, S., Plaschke, F., Russell, C. T., Guo, X-C, Lu, Q-M, Wang, C., Li, Wenya, Khotyaintsev, Yuri V., Tang, B-B, Graham, Daniel B., Norgren, C., Vaivads, A., André, Mats, Le, A., Egedal, J., Dokgo, K., Fujimoto, K., He, J-S, Burch, J. L., Lindqvist, P-A, Ergun, R. E., Torbert, R. B., Le Contel, O., Gershman, D. J., Giles, B. L., Lavraud, B., Fuselier, S., Plaschke, F., Russell, C. T., Guo, X-C, Lu, Q-M, and Wang, C.
- Abstract
Magnetic reconnection is a fundamental process in collisionless space plasma environment, and plasma waves relevant to the kinetic interactions can have a significant impact on the multiscale behavior of reconnection. Here, we present Magnetospheric Multiscale (MMS) observations during an encounter of an X line of symmetric magnetic reconnection in the magnetotail. The X line is characterized by reversals of ion and electron jets and electromagnetic fields, agyrotropic electron velocity distribution functions (VDFs), and an electron-scale current sheet. MMS observe large-amplitude nonlinear upper-hybrid (UH) waves on both sides of the neutral line, and the wave amplitudes have highly localized distribution along the normal direction. The inbound meandering electrons drive the UH waves, releasing the free energy stored from the reconnection electric field along the meandering trajectories. The interaction between the meandering electrons and the UH waves may modify the balance of the reconnection electric field around the X line. Plain Language Summary The electron-scale kinetic physics in the electron diffusion region (EDR) controls how magnetic field lines break and reconnect. Electron crescent, an indicator of EDR, can drive high-frequency electrostatic waves around EDR. For the first time, the upper-hybrid (UH) waves are observed on both sides of the X line and we show the direct association between the UH waves and the reconnection electric field. The strong wave-electron interaction can change the electron-scale dynamics and may modify the reconnection electric field. This study demonstrates that the UH waves may play an important role in controlling the reconnection rate.
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- 2021
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142. Microscale Processes Determining Macroscale Evolution of Magnetic Flux Tubes along Earth's Magnetopause
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Hwang, K. -J, Burch, J. L., Russell, C. T., Choi, E., Dokgo, K., Fear, R. C., Fuselier, S. A., Petrinec, S. M., Sibeck, D. G., Hasegawa, H., Fu, H., Oieroset, M., Escoubet, C. P., Giles, B. L., Khotyaintsev, Yuri V., Graham, Daniel B., Gershman, D. J., Pollock, C. J., Ergun, R. E., Torbert, R. B., Broll, J., Hwang, K. -J, Burch, J. L., Russell, C. T., Choi, E., Dokgo, K., Fear, R. C., Fuselier, S. A., Petrinec, S. M., Sibeck, D. G., Hasegawa, H., Fu, H., Oieroset, M., Escoubet, C. P., Giles, B. L., Khotyaintsev, Yuri V., Graham, Daniel B., Gershman, D. J., Pollock, C. J., Ergun, R. E., Torbert, R. B., and Broll, J.
- Abstract
An important process affecting solar wind-Earth's magnetosphere coupling is nonsteady dayside magnetic reconnection, observationally evidenced by a flux transfer event (FTE) that shows a bipolar variation of the magnetic field component normal to the magnetopause. FTEs often consist of two interlinked flux tubes, but, local kinetic processes between the flux tubes are not understood in the context of the FTE structuring, evolution, and impact. An FTE observed by the Magnetospheric Multiscale mission on 2017 December 18 consisted of two flux tubes of different topology. One includes field lines with ends connected to the northern and southern hemispheres while the other includes field lines with both ends connected to the magnetosheath. Reconnection occurring at the flux-tube interface indicates how interacting flux tubes evolve into a flux rope with helical magnetic topology that is either closed or open. This study demonstrates a new aspect of how micro- to meso-scale dynamics occurring within FTEs determines their macroscale characteristics and evolution.
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- 2021
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143. A Multi-Instrument Study of a Dipolarization Event in the Inner Magnetosphere
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Matsui, H., Torbert, R. B., Spence, H. E., Argall, M. R., Cohen, I. J., Cooper, M. B., Ergun, R. E., Farrugia, C. J., Fennell, J. F., Fuselier, S. A., Gkioulidou, M., Khotyaintsev, Yuri V., Lindqvist, P. -A, Matsuoka, A., Russell, C. T., Shoji, M., Strangeway, R. J., Turner, D. L., Vaith, H., Wygant, J. R., Matsui, H., Torbert, R. B., Spence, H. E., Argall, M. R., Cohen, I. J., Cooper, M. B., Ergun, R. E., Farrugia, C. J., Fennell, J. F., Fuselier, S. A., Gkioulidou, M., Khotyaintsev, Yuri V., Lindqvist, P. -A, Matsuoka, A., Russell, C. T., Shoji, M., Strangeway, R. J., Turner, D. L., Vaith, H., and Wygant, J. R.
- Abstract
A dipolarization of the background magnetic field was observed during a conjunction of the Magnetospheric Multiscale (MMS) spacecraft and Van Allen Probe B on September 22, 2018. The spacecraft were located in the inner magnetosphere at L similar to 6-7 just before midnight magnetic local time (MLT). The radial separation between MMS and Probe B was similar to 1R(E). Gradual dipolarization or an increase of the northward component B-Z of the background field occurred on a timescale of minutes. Exploration of energization and Radiation in Geospace located 0.5 MLT eastward at a similar L shell also measured a gradual increase. The spatial scale was of the order of 1 R-E. On top of that, MMS and Probe B measured B-Z increases, and a decrease in one case, on a timescale of seconds, accompanied by large electric fields with amplitudes > several tens of mV/m. Spatial scale lengths were of the order of the ion inertial length and the ion gyroradius. The inertial term in the momentum equation and the Hall term in the generalized Ohm's law were sometimes non-negligible. These small-scale variations are discussed in terms of the ballooning/interchange instability and kinetic Alfven waves among others. It is inferred that physics of multiple scales was involved in the dynamics of this dipolarization event.
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- 2021
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144. MMS Observations of Reconnection Separatrix Region in the Magnetotail at Different Distances From the Active Neutral X-Line
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Sergeev, V. A., Apatenkov, S. , V, Nakamura, R., Plaschke, F., Baumjohann, W., Panov, E. , V, Kubyshkin, I. , V, Khotyaintsev, Yuri V., Burch, J. L., Giles, B. L., Russell, C. T., Torbert, R. B., Sergeev, V. A., Apatenkov, S. , V, Nakamura, R., Plaschke, F., Baumjohann, W., Panov, E. , V, Kubyshkin, I. , V, Khotyaintsev, Yuri V., Burch, J. L., Giles, B. L., Russell, C. T., and Torbert, R. B.
- Abstract
The region surrounding the reconnection separatrix consists of many particle and wave transient features (electron, cold and hot ion beams, Hall E&B fields, kinetic Alfven, LH, etc. waves) whose pattern and parameters may vary depending on the distance from active neutral line. We study nine quick MMS entries into the plasma sheet boundary layer (PSBL) from the tail lobe to address the meso-scale pattern and other characteristics of phenomena for active separatrix crossings as deduced from particle observations. The outermost thin layer (a fraction of ion inertial scale, d(i)) of low-density plasma consists of accelerated electron beams and lobe cold ions and displays density depletions (EBL region). It is followed by hot proton beam (PBL region) in which the plasma density grows from lobe-like towards plasma sheet-like values; the beam energy-dispersion is used to estimate the distance from the active neutral line. Thin (usually <= d(i)) region containing intense Hall-like Ez perturbations (HR) usually overlaps with EBL and PBL regions. It often includes correlated B perturbations suggesting the Alfven wave-related transport from the reconnection source; the estimated Alfvenic ratio delta E/(V-A delta B) varied between 0.3 and 1.3 in studied examples. The HR is associated with profound plasma property changes, including the heating of cold ion beams in its innermost part, it hosts intense structured field-aligned currents and intense E-field fluctuations. Surprisingly, most of abovementioned findings are valid for crossings observed at large distances from the reconnection region (exceeding a few tens Re or >100 d(i)) except for longer time-scales and larger spatial scales of the pattern.
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- 2021
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145. Comparative Analysis of the Various Generalized Ohm's Law Terms in Magnetosheath Turbulence as Observed by Magnetospheric Multiscale
- Author
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Stawarz, J. E., Matteini, L., Parashar, T. N., Franci, L., Eastwood, J. P., Gonzalez, C. A., Gingell, I. L., Burch, J. L., Ergun, R. E., Ahmadi, N., Giles, B. L., Gershman, D. J., Le Contel, O., Lindqvist, Per-Arne, Russell, C. T., Strangeway, R. J., Torbert, R. B., Stawarz, J. E., Matteini, L., Parashar, T. N., Franci, L., Eastwood, J. P., Gonzalez, C. A., Gingell, I. L., Burch, J. L., Ergun, R. E., Ahmadi, N., Giles, B. L., Gershman, D. J., Le Contel, O., Lindqvist, Per-Arne, Russell, C. T., Strangeway, R. J., and Torbert, R. B.
- Abstract
Decomposing the electric field (E) into the contributions from generalized Ohm's law provides key insight into both nonlinear and dissipative dynamics across the full range of scales within a plasma. Using high-resolution, multispacecraft measurements of three intervals in Earth's magnetosheath from the Magnetospheric Multiscale mission, the influence of the magnetohydrodynamic, Hall, electron pressure, and electron inertia terms from Ohm's law, as well as the impact of a finite electron mass, on the turbulent E spectrum are examined observationally for the first time. The magnetohydrodynamic, Hall, and electron pressure terms are the dominant contributions to E over the accessible length scales, which extend to scales smaller than the electron gyroradius at the greatest extent, with the Hall and electron pressure terms dominating at sub-ion scales. The strength of the nonideal electron pressure contribution is stronger than expected from linear kinetic Alfven waves and a partial antialignment with the Hall electric field is present, linked to the relative importance of electron diamagnetic currents in the turbulence. The relative contribution of linear and nonlinear electric fields scale with the turbulent fluctuation amplitude, with nonlinear contributions playing the dominant role in shaping E for the intervals examined in this study. Overall, the sum of the Ohm's law terms and measured E agree to within similar to 20% across the observable scales. These results both confirm general expectations about the behavior of E in turbulent plasmas and highlight features that should be explored further theoretically., QC 20210412
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- 2021
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146. Determining EMIC Wave Vector Properties Through Multi‐Point Measurements: The Wave Curl Analysis
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Vines, S. K., primary, Anderson, B. J., additional, Allen, R. C., additional, Denton, R. E., additional, Engebretson, M. J., additional, Johnson, J. R., additional, Toledo‐Redondo, S., additional, Lee, J. H., additional, Turner, D. L., additional, Ergun, R. E., additional, Strangeway, R. J., additional, Russell, C. T., additional, Wei, H., additional, Torbert, R. B., additional, Fuselier, S. A., additional, Giles, B. L., additional, and Burch, J. L., additional
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- 2021
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147. An Encounter With the Ion and Electron Diffusion Regions at a Flapping and Twisted Tail Current Sheet
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Farrugia, C. J., primary, Rogers, A. J., additional, Torbert, R. B., additional, Genestreti, K. J., additional, Nakamura, T. K. M., additional, Lavraud, B., additional, Montag, P., additional, Egedal, J., additional, Payne, D., additional, Keesee, A., additional, Ahmadi, N., additional, Ergun, R., additional, Reiff, P., additional, Argall, M., additional, Matsui, H., additional, Wilson, L. B., additional, Lugaz, N., additional, Burch, J. L., additional, Russell, C. T., additional, Fuselier, S. A., additional, and Dors, I., additional
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- 2021
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148. Evidence for Nonadiabatic Oxygen Energization in the Near‐Earth Magnetotail From MMS
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Bingham, S. T., primary, Nikoukar, R., additional, Cohen, I. J., additional, Mauk, B. H., additional, Turner, D. L., additional, Mitchell, D. G., additional, Burch, J. L., additional, Gomez, R. G., additional, Fuselier, S. A., additional, and Torbert, R. B., additional
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- 2021
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149. MMS Observations of Reconnection Separatrix Region in the Magnetotail at Different Distances From the Active Neutral X‐Line
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Sergeev, V. A., primary, Apatenkov, S. V., additional, Nakamura, R., additional, Plaschke, F., additional, Baumjohann, W., additional, Panov, E. V., additional, Kubyshkin, I. V., additional, Khotyaintsev, Y., additional, Burch, J. L., additional, Giles, B. L., additional, Russell, C. T., additional, and Torbert, R. B., additional
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- 2021
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150. Polynomial Reconstruction of the Reconnection Magnetic Field Observed by Multiple Spacecraft
- Author
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Denton, R. E., Torbert, R. B., Dors, I., Genestreti, K. J., Argall, M., Gershman, D. J., Le, Contel O., Burch, J. L., Russell, C. T., Strangeway, R. J., Giles, B. L., Fischer, D., Hasegawa, Hiroshi, University of New Hampshire (UNH), Laboratoire des sciences et matériaux pour l'électronique et d'automatique (LASMEA), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS), EOS Space Science Center [Durham], Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU), Southwest Research Institute [San Antonio] (SwRI), Department of Earth, Planetary and Space Sciences [Los Angeles] (EPSS), University of California [Los Angeles] (UCLA), University of California-University of California, Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Physics ,Polynomial ,010504 meteorology & atmospheric sciences ,Spacecraft ,business.industry ,[PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,Magnetic reconnection ,Plasmoid ,01 natural sciences ,Magnetic field ,Computational physics ,Geophysics ,Space and Planetary Science ,0103 physical sciences ,business ,010303 astronomy & astrophysics ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences - Abstract
著者人数: 13名, Accepted: 2019-12-11, 資料番号: SA1190210000
- Published
- 2020
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