ﻻ يوجد ملخص باللغة العربية
In this study we present an inversion method which provides thermal plasma population parameters from characteristics of chorus emissions only. Our ultimate goal is to apply this method to ground based data in order to derive the lower energy boundary condition for many radiation belt models. The first step is to test the chorus-inversion method on in-situ data of Van Allen Probes in the generation region. Density and thermal velocity of energetic electrons (few keV - 100 keV) are derived from frequency sweep rate and starting frequencies of chorus emissions through analysis of wave data from Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) onboard the Van Allen Probes. Nonlinear wave growth theory of citet{omura2011triggering} serves as the basis for our inversion method, assuming that the triggering wave is originated by the linear cyclotron instability. We present sixteen, consecutive rising-tone emissions recorded in the generation region between 11-12UT on 14 November 2012. The results of the inversion are compared with density and thermal velocities (parallel and perpendicular) of energetic electrons derived from unidirectional flux data of Helium Oxygen Proton Electron (HOPE) instrument, showing a good agreement: the normalized root-mean-square deviation between the measured and predicted values are $sim13%, sim6%$, and $sim10%$, respectively. We found that the theoretical amplitudes are consistent with the measured ones. The relation between linear and nonlinear wave growth agrees with our basic assumption, namely, linear growth is a preceding process of nonlinear wave growth. We analyze electron distributions at the relativistic resonant energy ranges.
AIM: Large amplitude narrowband obliquely propagating whistler-mode waves at frequencies of ~0.2 fce (electron cyclotron frequency) are commonly observed at 1 AU, and are most consistent with the whistler heat flux fan instability. We want to determi
Heavy (O+) ion energization and field-aligned motion in and near the ionosphere are still not well understood. Based on observations from the CASSIOPE Enhanced Polar Outflow Probe (e-POP) at altitudes between 325 km and 730 km over one year, we prese
The nature of the turbulent energy transfer rate is studied using direct numerical simulations of weakly collisional space plasmas. This is done comparing results obtained from hybrid Vlasov-Maxwell simulations of colissionless plasmas, Hall-magnetoh
Waves around the lower hybrid frequency are frequently observed at Earths magnetopause, and readily reach very large amplitudes. Determining the properties of lower hybrid waves is crucial because they are thought to contribute to electron and ion he
We present a statistical analysis of more than two thousand bipolar electrostatic solitary waves (ESW) collected from ten quasi-perpendicular Earths bow shock crossings by Magnetospheric Multiscale spacecraft. We developed and implemented a correctio