Fast Plasma Investigation for Magnetospheric Multiscale

Dipolarization fronts (DFs) are important for energy conversion, particle acceleration, and flux transport in the magnetotail. The partition of energy conversion between ions and electrons and the energy dissipation at DFs are not well understood. In this paper, we present a statistical study of energy conversion and dissipation of 122 DFs observed by Magnetospheric Multiscale mission in the magnetotail. Statistically, electromagnetic energy transfers to plasma at DF. The released energy is mainly transferred to ions rather than electrons. On average, ions gain energy across the whole DF, while electrons gain energy at the leading part but lose energy at the trailing part of DFs. Joule dissipation J · (E+ve × B) can be either positive or negative at DFs, and its average value is very small. The kinetic energy dissipation parameter Pi − D does not exhibit clear signatures at the DFs; hence, it is not suitable for quantifying the energy dissipation at DF.

Section: Event Selectionmentioning

confidence: 99%

Energy Conversion and Dissipation at Dipolarization Fronts: A Statistical Overview

Zhong

Deng

Zhou

et al. 2019

“…Particle, magnetic field, and electric field data required in this study were acquired by the Fast Plasma Investigation (FPI), which cannot distinguish ion species (Pollock et al, 2016), the Hot Plasma Composition Analyzer (HPCA), which can (Young et al, 2016), the Flux Gate Magnetometers (FGM, Russell et al, 2016), and the Electric Field Double Probe (EDP; Ergun et al, 2016;Lindqvist et al, 2016), respectively, onboard the four MMS spacecraft. For HPCA and FGM, survey mode data are used; for FPI and EDP, fast mode data are used.…”

Section: Event Overviewmentioning

confidence: 99%

ULF Waves Modulating and Acting as Mass Spectrometer for Dayside Ionospheric Outflow Ions

Liu

Zong

Zhou

et al. 2019

Ionospheric outflow has been shown to be a dominant ion source of Earth's magnetosphere. However, most studies in the literature are about ionospheric outflow injected into the nightside magnetosphere. We still know little about ionospheric outflow injected into the dayside magnetosphere and its further energization after it enters the magnetosphere. Here, with data from Magnetospheric Multiscale mission, we report direct observations of the modulation of dayside ionospheric outflow ions by ultralow frequency (ULF) waves. The observations indicate that the modulation is mass dependent, which demonstrates the possibility of using ULF waves as a mass spectrometer to identify ion species. Moreover, the measurement suggests that polarization drift may play a role in O+ modulation, which may lead to a true acceleration and even nonadiabatic behavior of O+. This interaction scenario can work throughout the whole magnetosphere and impact upon the plasma environment and dynamics.

“…For 0.5 ce < < 0.6 ce , |V res | ranges from 4v the to 7v the . Figure 3a shows the 2-D electron distribution function measured by the Fast Plasma Investigation (FPI) (Pollock et al, 2016). For electrons with a low speed (v e < 3v the ; v e is the electron speed; v the ∼ 4 × 10 6 m/s), contours of the phase space density (f e ) are elongated along the parallel direction, indicating T ∥ > T ⟂ for these electrons.…”

Section: Figures 2c and 2dmentioning

confidence: 99%

Whistler Wave Generation by Anisotropic Tail Electrons During Asymmetric Magnetic Reconnection in Space and Laboratory

Yoo

Jara-Almonte

Yerger

et al. 2018

Whistler wave generation near the magnetospheric separatrix during reconnection at the dayside magnetopause is studied with data from the Magnetospheric Multiscale mission. The dispersion relation of the whistler mode is measured for the first time near the reconnection region in space, which shows that whistler waves propagate nearly parallel to the magnetic field line. A linear analysis indicates that the whistler waves are generated by temperature anisotropy in the electron tail population. This is caused by loss of electrons with a high velocity parallel to the magnetic field to the exhaust region. There is a positive correlation between activities of whistler waves and the lower hybrid drift instability both in laboratory and space, indicating the enhanced transport by lower hybrid drift instability may be responsible for the loss of electrons with a high parallel velocity.