Theoretical astrophysics and plasma physics at RPC

Abstract:

A collection of input files, and instructions on how to use them, for the manuscript entitled 'A novel approach to radially global gyrokinetic simulation using the flux-tube code stella'. These input files, which are designed for the gyrokinetic flux-tube code stella, are specifically for the simulations resulting in figures 2-10.

Abstract:

We report on six dipolarization fronts (DFs) embedded in fast earthward flows detected by the Magnetospheric Multiscale mission during a substorm event on 23 July 2017. We analyzed Ohm's law for each event and found that ions are mostly decoupled from the magnetic field by Hall fields. However, the electron pressure gradient term is also contributing to the ion decoupling and likely responsible for an electron decoupling at DF. We also analyzed the energy conversion process and found that the energy in the spacecraft frame is transferred from the electromagnetic field to the plasma (J·E>0) ahead or at the DF, whereas it is the opposite (J·E<0) behind the front. This reversal is mainly due to a local reversal of the cross-tail current indicating a substructure of the DF. In the fluid frame, we found that the energy is mostly transferred from the plasma to the electromagnetic field (J·E′<0) and should contribute to the deceleration of the fast flow. However, we show that the energy conversion process is not homogeneous at the electron scales due to electric field fluctuations likely related to lower-hybrid drift waves. Our results suggest that the role of DF in the global energy cycle of the magnetosphere still deserves more investigation. In particular, statistical studies on DF are required to be carried out with caution due to these electron scale substructures.

Abstract:

Supplementary data for the article "Extended electron tails in electrostatic microinstabilities and the nonadiabatic response of passing electrons": arXiv 2108.02822. The dataset includes a readme, GS2 FORTRAN namelist input files necessary to reproduce the simulations presented in the article, as well as scripts (using a mixture of Mathematica, MATLAB, and Python) for the calculation of collisional transport coefficients that appear in the collisional theory of the studied microinstabilities.