@InProceedings{AlvesAlve:2022:ImPiAn,
author = "Alves, Livia Ribeiro and Alves, M{\'a}rcio E. S.",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and
{Universidade Estadual Paulista (UNESP)}",
title = "Interaction Time of Relativistic Electrons and Whistler-Mode
Chorus Waves in the Radiation Belt: Implications for the Pitch
Angle Scattering",
year = "2022",
organization = "AGU Fall Meeting",
publisher = "AGU",
abstract = "The inner portion of the Earth's magnetic field has a dipolar
configuration. It traps electrons of a broad energy range, from
10's of keV to 10's of MeV, in the outer radiation belt. The
source of the trapped electrons is mainly the solar wind. The
low-energy electrons (10's of keV) are transported throw the
interplanetary media toward the magnetosphere. These particles
reach inside the magnetosphere through magnetic reconnection.
Magnetospheric convection, adiabatic motion, and wave-particle
diffusion transport the electrons from the outskirts of the
magnetosphere to the inner region. Low energy electrons produce
whistler-mode chorus waves, hereafter named chorus waves, due to
plasma temperature anisotropy and the loss cone instability.
Chorus waves are very low frequency (~0.1 - 1 kHz) in
whistler-mode, observed outside the plasmasphere, mainly at the
dawn side magnetosphere. The wave-particle interaction can
accelerate electrons seed population (100's of keV) to MeV
energies. Additionally, the electrons can reach the loss-cone
pitch angles and precipitate into the atmosphere. The
wave-particle interaction succeeds when the resonance condition
between the electron gyrofrequency and the wave frequency is
achieved. The interaction time is a crucial parameter in
estimating wave-particle interaction efficiency. The interaction
occurs in the electron's reference frame, while the measurements
are made in the satellite's frame. Therefore, we perform the
necessary relativistic corrections coming from the frame change. A
test particle approach is used to evaluate the variation of the
electron's pitch angle scattering due to chorus waves propagating
parallel to the ambient magnetic field. We apply wave-particle
resonance conditions for different plasma densities to calculate
the correspondent kinetic energy. Thus, in-situ measurements of
the ambient plasma medium, chorus waves, and electron fluxes are
used to estimate the interaction time. We also evaluate the error
using the non-relativistic formulas for similar estimates. Our
results show that the error in the interaction time scales with
the electron's kinetic energy. The error can be higher than one
order of magnitude for 400 keV low-energy electrons, which
corresponds to the same magnitude error in the change in pitch
angle.",
conference-location = "Chicago, IL",
conference-year = "12-16 Dec. 2022",
urlaccessdate = "05 jun. 2024"
}