When Coulomb collisions between particles become negligible in a plasma, the particle distribution functions do not easily relax to Maxwellian distributions, and the MHD formalism fails to appropriately describe the plasma. Several processes, including magnetic reconnection, wave-particle interactions at kinetic scales, or turbulent cascading become the dominant mechanisms for energy exchange between populations and plasma regions in this regime. The Earth's magnetosphere and magnetosheath are composed of fully ionized, collisionless, plasmas. They constitute a natural laboratory for investigating these processes, which are generally non-linear. We invite abstracts discussing the kinetic nature of the plasma processes that occur in the Earth's magnetosphere and its surroundings. We encourage studies taking advantage of spacecraft measurements (e.g., MMS, Van Allen Probes, ARASE, THEMIS, Cluster, Geotail), modelling using kinetic simulations (e.g, Particle-In-Cell, Vlasov equation solvers) as well as analytical works.

Convener: Sergio Toledo-Redondo | Co-conveners: Kyoung-Joo (Joo) Hwang, Yuri Khotyaintsev, Rumi Nakamura
| Attendance Tue, 05 May, 10:45–12:30 (CEST)

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Chat time: Tuesday, 5 May 2020, 10:45–12:30

Chairperson: S. Toledo-Redondo
D2967 |
| solicited
| Highlight
Wenya Li, Daniel Graham, Binbin Tang, Andris Vaivads, Mats Andre, Kyungguk Min, Kaijun Liu, Keizo Fujimoto, Per Arne Lindqvist, Kyunghwan Dokgo, Chi Wang, and James Burch

The Magnetospheric Multiscale spacecraft encounter an electron diffusion region (EDR) of asymmetric magnetic reconnection at Earth's magnetopause. The EDR is characterized by agyrotropic electron velocity distributions on both sides of the neutral line. Various types of plasma waves are produced by the magnetic reconnection in and near the EDR. Here we report large-amplitude electron Bernstein waves (EBWs) at the electron-scale boundary of the Hall current reversal. The finite gyroradius effect of the outflow electrons generates the crescent-shaped agyrotropic electron distributions, which drive the EBWs. The EBWs propagate toward the central EDR. The amplitude of the EBWs is sufficiently large to thermalize and diffuse electrons around the EDR. Our analysis shows that the EBWs contribute to the cross-field diffusion of the electron-scale boundary of the Hall current reversal near the EDR.

How to cite: Li, W., Graham, D., Tang, B., Vaivads, A., Andre, M., Min, K., Liu, K., Fujimoto, K., Lindqvist, P. A., Dokgo, K., Wang, C., and Burch, J.: Electron Bernstein Waves driven by Electron Crescents near the Electron Diffusion Region, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4295, https://doi.org/10.5194/egusphere-egu2020-4295, 2020.

D2968 |
Giulia Cozzani, Alessandro Retinò, Francesco Califano, Alexandra Alexandrova, Yuri Khotyaintsev, Mats André, Filomena Catapano, Huishan Fu, Olivier Le Contel, Andris Vaivads, Narges Ahmadi, and Hugo Breuillard and the MMS Team

Magnetic reconnection is a fundamental energy conversion process in plasmas. It occurs in thin current sheets, where a change in the magnetic field topology leads to rapid heating of plasma, plasma bulk acceleration and acceleration of plasma particles. To allow for magnetic field reconfiguration, both ions and electrons must be demagnetized. The ion and electron demagnetization  take place in the ion and electron diffusion regions respectively, in both cases at kinetic scales. For the first time, Magnetospheric Multiscale (MMS) spacecraft observations, at inter-spacecraft separation comparable to the electron inertial length, allow for a multi-point analysis of the electron diffusion region (EDR). A key question is whether the EDR has a homogeneous or patchy structure. 

Here we report MMS observations at the magnetopause providing evidence of inhomogeneous current densities and energy conversion over a few (∼ 3 de) electron inertial lengths suggesting that the EDR can be structured at electron scales. In particular, the energy conversion is patchy and changing sign in the vicinity of the reconnection site implying that the EDR comprises regions where energy is transferred from the field to the plasma and regions with the opposite energy transition, which is unexpected during reconnection. The origin of the patchy energy conversion appears to be connected to the large ve,N ∼ ve,M directed from the magnetosphere to magnetosheath. These observations are consistent with recent high-resolution and low-noise kinetic simulations of asymmetric reconnection. Patchy energy conversion is observed also in an EDR at the magnetotail, where the inter-spacecraft separation was ∼ 1 de. Electric field measurements are different among the spacecraft suggesting inhomogeneities at the electron scale. However, in this case the current density appear homogeneous in the EDR suggesting that the structuring may be sourced from a different kind of electron dynamics in the magnetotail.

How to cite: Cozzani, G., Retinò, A., Califano, F., Alexandrova, A., Khotyaintsev, Y., André, M., Catapano, F., Fu, H., Le Contel, O., Vaivads, A., Ahmadi, N., and Breuillard, H. and the MMS Team: In situ spacecraft observations of structured electron diffusion regions during magnetic reconnection, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13405, https://doi.org/10.5194/egusphere-egu2020-13405, 2020.

D2969 |
Jinghuan Li, Fan Yang, Xu-Zhi Zhou, Qiu-Gang Zong, Anton V. Artemyev, Robert Rankin, Quanqi Shi, Shutao Yao, Han Liu, Jiansen He, Zuyin Pu, and Chijie Xiao

Magnetic cavities, sometimes referred to as magnetic holes, are ubiquitous in space and astrophysical plasmas characterized by localized regions with depressed magnetic field strength, strongly anisotropic particle distributions, and enhanced plasma pressure. Typical cavity sizes range from fluid to ion and sub-ion kinetic scales, with recent observations also identifying nested cavities that may indicate cross-scale energy cascades. Although heavily investigated in space, magnetic cavities have analogs in laboratory plasmas, the classical theta-pinches. Here, we develop an equilibrium solution of the Vlasov-Maxwell equations in cylindrical coordinates (in similar format to theta-pinch models), to reconstruct the cross-scale profiles of magnetic cavities observed by the four-spacecraft MMS mission. The kinetic model uses input parameters derived from single-spacecraft measurements to successfully reproduce signatures of magnetic cavities from all observing spacecraft. The reconstructed profiles demonstrate that near the electron-scale cavity boundary, the decoupled electron and proton motions generate a radial electric field that contributes to electron vortex formation that has been previously attributed mostly to diamagnetic effects. At larger scales, the diminishing electric field implies that diamagnetic motion is solely responsible for proton vortices.

How to cite: Li, J., Yang, F., Zhou, X.-Z., Zong, Q.-G., Artemyev, A. V., Rankin, R., Shi, Q., Yao, S., Liu, H., He, J., Pu, Z., and Xiao, C.: Electron- and proton-scale nested magnetic cavities: Manifestation of kinetic theta-pinch equilibrium in space plasmas, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3846, https://doi.org/10.5194/egusphere-egu2020-3846, 2020.

D2970 |
| Highlight
Takuma Nakamura, Takayuki Umeda, Rumi Nakamura, Huishan Fu, and Mitsuo Oka

Magnetic reconnection is a key process in collisionless plasmas that converts magnetic energy to plasma kinetic energies through changes in the magnetic field topology. The energy conversion in this process is believed to cause various explosive phenomena in space such as auroral substorms in the Earth’s magnetosphere and solar flares. Here, a 3D fully kinetic simulation shows that the lower-hybrid drift instability (LHDI) disturbs the front of magnetic reconnection outflow jets and additionally causes the energy dissipation. The peak energy dissipation at the jet fronts is comparable to the values seen near the center of the reconnection region where the topology change during reconnection occurs, indicating that the LHDI turbulence has a substantial effect on the energetics of reconnection. The result is well consistent with a disturbance observed at the dipolarization front (DF) in the Earth’s magnetotail by the Magnetospheric Multiscale (MMS) mission. A fully kinetic dispersion relation solver, validated by the MMS observations, further predicts that the disturbance of the reconnection jet front could occur over different parameter regimes in space plasmas including the Earth’s DF and solar flares.

How to cite: Nakamura, T., Umeda, T., Nakamura, R., Fu, H., and Oka, M.: Disturbance of the front region of magnetic reconnection outflow jets due to the lower-hybrid drift instability, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2848, https://doi.org/10.5194/egusphere-egu2020-2848, 2020.

D2971 |
Sid Fadanelli, Benoit Lavraud, and Francesco Califano

We present an analysis of energy transfers in a reconnecting near-Earth plasma, obtained by interpreting MMS data within the framework of multi-fluid plasma theory. In our analysis, energy transfers are calculated and examined locally. This way, correlations between different mechanisms of energy exchange can be retrieved in all spatial and temporal detail provided by the high-frequency, multi-point sampling capacity of the four MMS satellites.
In particular, compressional effects are separated from effective sources in the energy density evolution equations, allowing to distinguish whether some effective energy transfer is occurring locally. A large database of MMS encounters with reconnecting current sheets is exploited in order to assess the statistical validity of all results presented.

How to cite: Fadanelli, S., Lavraud, B., and Califano, F.: A multi-spacecraft analysis of energy transfer associated with near-Earth magnetic reconnection, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-16698, https://doi.org/10.5194/egusphere-egu2020-16698, 2020.

D2972 |
Daniel Graham, Yuri Khotyaintsev, Andris Vaivads, Mats Andre, Ahmad Lalti, Andrew Dimmock, and Andreas Johlander

At Earth’s bow shock electrons can be reflected and accelerated along magnetic fields lines, which can then form electron beams and excite Langmuir and beam-mode waves. These electron beams form when the shock normal angle is close to 90 degrees. However, recent observations have shown that quasi-perpendicular shocks can be non-stationary and exhibit ripples, which can modify the local shock-normal angle and cross-shock potential. We use Magnetospheric Multiscale (MMS) data to investigate the effects of shock ripples on the accelerated electrons observed in the electron foreshock. We compare the results with test-particle simulations to determine the effect of shock ripples on electron acceleration. We discuss the implications of these results for the generation of plasma frequency waves and radio emission in the electron foreshock region. 

How to cite: Graham, D., Khotyaintsev, Y., Vaivads, A., Andre, M., Lalti, A., Dimmock, A., and Johlander, A.: Effect of shock ripples on electron acceleration and reflection at the quasi-perpendicular bow shock, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11510, https://doi.org/10.5194/egusphere-egu2020-11510, 2020.

D2973 |
Xochitl Blanco-Cano, Luis Preisser, Diana Rojas-Castillo, and Primoz Kajdic

Earth's magnetosheath is permeated by a variety of plasma waves, nonlinear structures and ion distributions.  Understanding solar wind interaction with Earth's magnetic field requires a detailed knowledge of the magnetosheath as the interface between both regions, including its kinetic micro-structure. In this work we study an extended interval (45 min) with southward magnetic field (Bz< 0) observed by MMS in the dayside magnetosheath. We use magnetic field and plasma data to study the properties of three transient enhancements in dynamic pressure identified as jets. We also calculate instability thresholds and investigate wave characteristics inside and outside of the jets. The characteristics of these jets are variable, which suggest different origins. While two of them can be classified as V-jets with large increment in velocity with almost no density increment the third one is an N-jet showing large enhancements in density with almost no velocity increment. The N-jet lasts seven times longer than the V-jets and occurs just at the region where the negative Bz becomes positive. Ion distributions inside the jets are more isotropic (Tperp ≈Tparallel) compared with the surrounding plasma where Tperp > Tparallel. FFT and minimum variance analysis show that fluctuations inside the N-jet tend to have larger transversal components, although they propagate at large angles to the background field. In contrast, waves in regions surrounding the jets are compressive and can be identified as elliptically polarized mirror mode waves. We have also show that the mirror instability threshold CM is positive inside these intervals.

How to cite: Blanco-Cano, X., Preisser, L., Rojas-Castillo, D., and Kajdic, P.: Magnetosheath kinetic structure: Mirror mode and jets during southward IP magnetic field, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11777, https://doi.org/10.5194/egusphere-egu2020-11777, 2020.

D2974 |
Evgeny Gordeev, Andrey Divin, Ivan Zaitsev, Vladimir Semenov, Yuri Khotyaintsev, and Stefano Markidis

Separatrices of magnetic reconnection host intense perpendicular Hall electric fields produced by decoupling of ion and electron components and associated with the in-plane electrostatic potential drop between inflow and outflow regions. The width of these structures is several local electron inertial lengths, which is small enough to demagnetize ions as they cross the layer. We investigate temperature dependence of ion acceleration at separatrices by means of 2D Particle-in-Cell (PIC) simulations of magnetic reconnection with only cold or hot ion background population. The separatrix Hall electric field is balanced by the inertia term in cold background simulations, the effect indicative of the quasi-steady local perpendicular acceleration. The electric field introduces a cross-field beam of unmagnetized particles which makes the temperature strongly non-gyrotropic and susceptible to sub-ion scale instabilities. This acceleration mechanism nearly vanishes for hot ion background simulations. Particle-in-cell simulations are complemented by one-dimensional test particle calculations, which show that the hot ion particles experience scattering in energies after crossing the accelerating layer, whereas cold ions are uniformly energized up to the energies comparable to the electrostatic potential drop between the inflow and outflow regions.

How to cite: Gordeev, E., Divin, A., Zaitsev, I., Semenov, V., Khotyaintsev, Y., and Markidis, S.: Acceleration of cold ions at separatrices of symmetric collisionless magnetic reconnection, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18886, https://doi.org/10.5194/egusphere-egu2020-18886, 2020.

D2975 |
Mats André, Sergio Toledo-Redondo, and Andrew W Yau

Cold (eV) ions of ionospheric origin dominate the number density of most of the volume of the magnetosphere during most of the time. Supersonic flows of cold positive ions are common and can cause a negatively charged wake behind a positively charged spacecraft. The associated induced electric field can be observed and can be used to study the cold ions. We present observations from the Cluster and MMS spacecraft showing how a charged satellite, and also individual charged wire booms of  an electric field instrument, can be used to investigate cold ion populations. Ionospheric ions affect large scales, including the Alfvén velocity and  thus energy transport with waves and the magnetic reconnection rate. These ions also affect small-scale kinetic plasma physics, including the Hall physics and wave instabilities associated with magnetic reconnection. Concerning large scales, we summarize observations from several spacecraft and show that a typical total outflow rate of ionospheric ions is 1026 ions/s and that many of these ions stay cold also after a long time in the magnetosphere.  Concerning small scales, we show examples of how cold ions modify the Hall physics of thin current sheets, including magnetic reconnection separatrices. On small kinetic scales the cold ions introduce a new length-scale, a gyro radius between the gyro radii of hot (keV) ions and electrons. The Hall currents carried by electrons can be partially cancelled by the cold ions when electrons and the magnetized cold ions ExB drift together. Also, close to a reconnection X-line an additional diffusion region can be formed (regions associated with hot and cold ions, and with electrons, total of three).

How to cite: André, M., Toledo-Redondo, S., and Yau, A. W.: Ionospheric ions in the magnetosphere: Important at large and small scales , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3653, https://doi.org/10.5194/egusphere-egu2020-3653, 2020.

D2976 |
Sergio Toledo-Redondo, Justin Lee, Sarah Vines, Drew Turner, Robert Allen, Wenya Li, Scott Boardsen, Mats Andre, Stephen Fuselier, Benoit Lavraud, Daniel Gershman, Adolfo Viñas, Olivier Lecontel, Barbara Giles, and James Burch

The Earth’s magnetosphere is constantly supplied by plasma coming from the solar wind and from the ionosphere. The ionospheric supply is typically cold and contains heavy ions, which can be often found in most parts of the magnetosphere.

Electromagnetic Ion Cyclotron (EMIC) waves occur in the outer magnetosphere, often in association with ionospheric ions, and serve as a coupling mechanism to the ionosphere and inner magnetosphere. Using the MMS spacecraft, we investigate the dynamics of these waves when ionospheric ions are present, and resolve their motion and energy exchange with the electromagnetic fields below the ion scale. We find that ring current ions and ionospheric ions have different dynamics inside an EMIC wave packet near the magnetopause, affecting the dispersion relation of the wave. We compare the observations to linear dispersion theory, and find excellent agreement between both. Cold ions are accelerated and drain energy from the wave packet, and modify the intrinsic properties such as the wave normal angle and the polarization of the wave.





How to cite: Toledo-Redondo, S., Lee, J., Vines, S., Turner, D., Allen, R., Li, W., Boardsen, S., Andre, M., Fuselier, S., Lavraud, B., Gershman, D., Viñas, A., Lecontel, O., Giles, B., and Burch, J.: Cold ion dynamics and interaction with EMIC waves near the Earth's magnetopause, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21818, https://doi.org/10.5194/egusphere-egu2020-21818, 2020.

D2977 |
Liudmila Rakhmanova, Maria Riazantseva, Georgy Zastenker, and Yuri Yermolaev

Large set of in-situ measurements with high time resolution in the Earth's magnetosheath provides a great opportunity to explore influence of kinetic processes on the turbulent cascade in the collisionless plasma. Recent statistical studies reveal dependence of characteristics of the turbulent spectra on position of the viewing point behind the bow shock. Detailed analysis of dynamics of the turbulence inside the magnetosheath requires a case study prepared in several points. Present study deals with in-situ measurements of kinetic-scale fluctuations in two points located close to one stream line in different parts of the magnetosheath. We analyze fluctuation spectra of ion flux value and magnetic field magnitude in the frequency range 0.01-2 Hz obtained simultaneously from Spektr-R and Themis spacecraft. The range of frequencies corresponds to transition from magnetohydrodynamic range of scales to the scales where kinetic effects become dominant. We demonstrate deviation of turbulent cascade from the shape predicted typically by the models of developed turbulence in the vicinity of the bow shock and in the subsolar magnetosheath. We show the recovery of the spectral shape during plasma propagation toward the tail. Also, we consider influence of the upstream solar wind conditions on the evolution of turbulence in the magnetosheath.

How to cite: Rakhmanova, L., Riazantseva, M., Zastenker, G., and Yermolaev, Y.: Kinetic-scale plasma turbulence evolving in the magnetosheath: case study, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-509, https://doi.org/10.5194/egusphere-egu2020-509, 2020.

D2978 |
Steven Petrinec, James Burch, Michael Chandler, Charlie Farrugia, Stephen Fuselier, Barbara Giles, Roman Gomez, Joey Mukherjee, William Paterson, Christopher Russell, David Sibeck, Robert Strangeway, Roy Torbert, Karlheinz Trattner, Sarah Vines, and Cong Zhao

Several dayside magnetosheath flux transfer events (FTEs) have been observed at high temporal resolution by the four-spacecraft MMS mission. In this study, we examine ion energy spectrograms, ion moments, and ion distribution functions for several long duration magnetosheath FTEs observed by MMS. For these cases, the spacecraft were positioned at similar locations (i.e., south of the equatorial plane, post-noon local time sector). The ion observations are placed in context with electron energy spectrograms parallel and anti-parallel to the observed magnetic field and the location of MMS relative to the predicted reconnection line location as determined from convected solar wind conditions. This combined set of observations provide important information on the formation, topologies, and evolution of FTEs.

How to cite: Petrinec, S., Burch, J., Chandler, M., Farrugia, C., Fuselier, S., Giles, B., Gomez, R., Mukherjee, J., Paterson, W., Russell, C., Sibeck, D., Strangeway, R., Torbert, R., Trattner, K., Vines, S., and Zhao, C.: Minor Ion and Electron Characteristics within Magnetosheath Flux Transfer Events Observed by the Magnetospheric Multiscale Mission, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20941, https://doi.org/10.5194/egusphere-egu2020-20941, 2020.

D2979 |
| Highlight
Rungployphan Kieokaew, Benoit Lavraud, and Naïs Fargette

A bipolar magnetic variation Bn with enhanced core and total fields in spacecraft data are recognized as a Flux Transfer Event (FTE) signature, which corresponds to the passage of a magnetic flux rope structure. Recent literature reported Magnetospheric Multiscale (MMS) observations of FTE signatures with magnetic reconnection signatures at the central current sheet. Among reported cases, electron pitch angle distributions (ePAD) in the suprathermal energy range show different features on either side of the reconnecting current sheet, indicating different magnetic connectivities. This structure is interpreted as interlinked/interlaced flux tubes, possibly formed by converging jets toward the central current sheet that in turn enhance magnetic flux pile-up and facilitate reconnection at the current sheet separating the two flux tubes. By surveying similar events using MMS data, we found some FTE-type structures with reconnection signatures at the central current sheet but with homogeneous ePAD of suprathermal electrons across the structures. Thus, these structures are inconsistent with interlinked flux tubes, but rather a regular flux rope. This leads to a question of how reconnection can occur in those single flux ropes, and their relation with interlinked flux tubes. In this work, we investigate properties of these structures and their related upstream solar-wind conditions. Formation mechanisms of such structures and how reconnection can occur will be discussed.

How to cite: Kieokaew, R., Lavraud, B., and Fargette, N.: MMS Observations of FTE-Type Structures with Internal Magnetic Reconnection, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-15878, https://doi.org/10.5194/egusphere-egu2020-15878, 2020.

D2980 |
| Highlight
Ahmad Lalti, Yuri Khotyaintsev, Daniel Graham, Andris Vaivads, Andreas Johlander, Roy Torbert, Barbara Giles, Chris Russell, and Jim Burch

The process of transforming the bulk kinetic energy of solar wind into the random motion of the plasma particles is still an open question. One of the proposed mechanisms for energy dissipation in such shocks is wave-particle interactions. Specifically reflected ions at the foot of the shock could interact with the solar wind plasma in an unstable way causing an increase in the temperature of the upstream plasma. Phase standing Whistler precursor waves upstream of the shock front could play a major role in enhancing energy dissipation. We analyze multiple shock crossing events encountered by the Magnetospheric Multiscale (MMS) multi-spacecraft Mission, with Alfvenic Mach numbers around 4 and a θBn around 80 degrees. We use these events to study the effect of such waves on energy dissipation at quasi perpendicular shocks.  Using spectral analysis and by calculating the poynting flux of the waves, we investigate the upstream shock energy transport by whistler waves, then we discuss the consequences of these results on the wave particle interaction as a mechanism for stabilizing such high Mach number shocks.

How to cite: Lalti, A., Khotyaintsev, Y., Graham, D., Vaivads, A., Johlander, A., Torbert, R., Giles, B., Russell, C., and Burch, J.: Effect of whistler precursor waves on energy dissipation in supercritical quasi-perpendicular collisionless shocks., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7452, https://doi.org/10.5194/egusphere-egu2020-7452, 2020.

D2981 |
Alexander Lukin, Anton Artemyev, Evgeny Panov, Anatoly Petrukovich, and Rumi Nakamura

Thermal and subthermal electron populations in the Earth’s magnetotail is usually characterized by pronounced field-aligned anisotropy that contributes to generation of strong electric currents within the magnetotail current sheet. Formation of this anisotropy requires electron field-aligned acceleration, and thus likely involves field-aligned electric fields. Such fields can be carried by various electromagnetic waves generated by fast plasma flows interacting with ambient magnetotail plasma. In this presentation we consider one of the most intense observed wave emissions, kinetic Alfven waves, that accompany all fast plasma flows in the magnetotail.

Using two tail seasons (2018, 2019) of MMS observations we have collected statistics of 80 fast plasma flows (or BBF) events with distinctive enhancement of intensity of broadband electromagnetic waves sharing properties of kinetic Alfven waves. We show that a direct correlation the intensity of electric fields of kinetic Alfven waves and electron anisotropy distribution: the parallel electron anisotropy significantly increases with magnitude of the wave parallel electric field. The energy range of this electron anisotropic population is well within the range of resonant energies for observed kinetic Alfven waves. Our results show that kinetic Alfven waves can significantly contribute to shaping the magnetotail electron population.

How to cite: Lukin, A., Artemyev, A., Panov, E., Petrukovich, A., and Nakamura, R.: Electron anisotropy driven by kinetic Alfven waves in the Earth magnetotail, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7680, https://doi.org/10.5194/egusphere-egu2020-7680, 2020.

D2982 |
Evgeny V. Panov, San Lu, and Philip L. Pritchett

How to cite: Panov, E. V., Lu, S., and Pritchett, P. L.: Observations of Magnetotail Interchange Heads' Signatures at Later Stage of Development, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8260, https://doi.org/10.5194/egusphere-egu2020-8260, 2020.

D2983 |
Pavel Shustov, Ilya Kuzichev, Ivan Vasko, Anton Artemyev, and Anatoliy Petrukovich

Electron holes are nonlinear electrostatic structures that are often observed in the vicinity of the magnetotail energy release regions, e.g. magnetic reconnection. In this work we develop 1.5D Vlasov code simulations of the electron hole dynamics in the magnetic field configuration typical of the current sheet of the Earth's magnetotail. We consider the propagation of electron holes along magnetic field lines in the inhomogeneous magnetic field of the current sheet with realistically anisotropic electron distribution function. We demonstrate that electron holes generated near the equatorial plane of the current sheet brake as they propagate toward the boundaries of the current sheets. This effect is stronger for higher magnetic field gradient and larger electron field-aligned anisotropy. These simulations demonstrate that slow electron holes observed in the plasma sheet boundary layer may appear due to that effect of electron hole braking.

How to cite: Shustov, P., Kuzichev, I., Vasko, I., Artemyev, A., and Petrukovich, A.: Electron holes in the Earth's magnetotail current sheet: role of magnetic field gradients and electron anisotropy, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11967, https://doi.org/10.5194/egusphere-egu2020-11967, 2020.

D2984 |
Olivier Le Contel, Alessandro Retino, Alexandra Alexandrova, Thomas Chust, Konrad Steinvall, Soboh Alqeeq, Patrick Canu, Dominique Fontaine, iannis Dandouras, Christopher Carr, Sergio Toledo, Andrew Fazakerley, Natasha Doss, Stefan Kiehas, Rumi Nakamura, Yuri Khotyaintsev, Frederick Wilder, Narges Ahmadi, Daniel Gershman, and Robert Strangeway and the Cluster/MMS team

On 28th of August 2018 at 5:30 UT, MMS and Cluster were located in the magnetotail at about 16 earth radii (RE). They both suddenly crossed plasma interfaces. Located in the post midnight sector, Cluster transitioned from a cold plasma sheet to a hot plasma sheet whereas MMS, located at 4 RE duskward of Cluster, transitioned from a similar cold plasma sheet to the lobe region via a very short period in a hot plasma sheet. At 05:50 UT MMS returned to a hot plasma sheet and detected a quasi-parallel earthward flow ~ 400 km/s and increased energetic ion and electron fluxes. We use measurements from both missions during this conjunction to describe the possible macroscale evolution of the magnetotail as well as some associated kinetic processes. In particular, we analyze fast and slow non linear electrostatic waves propagating tailward which are detected in the so called electron boundary layer as well as in the hot plasma sheet. We discuss their possible generation mechanisms and link with the large scale evolution of the magnetotail. Finally, we investigate possible effects related to the dawn-dusk asymmetry of the magnetotail.

How to cite: Le Contel, O., Retino, A., Alexandrova, A., Chust, T., Steinvall, K., Alqeeq, S., Canu, P., Fontaine, D., Dandouras, I., Carr, C., Toledo, S., Fazakerley, A., Doss, N., Kiehas, S., Nakamura, R., Khotyaintsev, Y., Wilder, F., Ahmadi, N., Gershman, D., and Strangeway, R. and the Cluster/MMS team: MMS/Cluster joint measurements at the vicinity of the plasma sheet boundary layer, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18357, https://doi.org/10.5194/egusphere-egu2020-18357, 2020.

D2985 |
Soboh Alqeeq, Olivier Le Contel, Patrick Canu, Alessandro Retino, Thomas Chust, and Laurent Mirioni and the MMS team

In July 2017, the MMS constellation was in the magnetotail with an apogee of 25 Earth radii
and an average inter-satellite distance of 10 km (i.e. at electron scales). On 23 July around
16:19 UT, MMS was located at the edge of the current sheet which was in a quasi-static
state. Then, MMS suddenly entered in the central plasma sheet and detected the local onset
of a small substorm as indicated by the AE index (~400 nT). Fast earthward plasma flows
were measured for about 1 hour starting with a period of quasi-steady flow and followed by
a saw-tooth like series of fast flows associated with dipolarization fronts. This plasma
transport sequence finished with a flow reversal still occurring close to the magnetic
equator. In the present study, we investigate the energy conversion processes at ion and
electron scales for these different phases with particular attention on the processes in the
vicinity of the dipolarization fronts.

How to cite: Alqeeq, S., Le Contel, O., Canu, P., Retino, A., Chust, T., and Mirioni, L. and the MMS team: Analysis of energy conversion processes at kinetic scales associated with a series of dipolarization fronts observed by MMS during a substorm, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19750, https://doi.org/10.5194/egusphere-egu2020-19750, 2020.