Evolution of energetic electron pitch angle distributions during storm time electron acceleration to megaelectronvolt energies

2003 ◽  
Vol 108 (A1) ◽  
Author(s):  
Richard B. Horne
Keyword(s):  
Pitch Angle ◽  
Energetic Electron ◽  
Electron Acceleration

Energetic Electron Pitch Angle Distributions During the Cassini Final Orbits

2018 ◽  
Vol 45 (7) ◽  
pp. 2911-2917 ◽  
Author(s):  
J. F. Carbary ◽  
D. G. Mitchell ◽  
P. Kollmann ◽  
N. Krupp ◽  
E. Roussos ◽  
...  
Keyword(s):  
Pitch Angle ◽  
Energetic Electron

scholarly journals Pitch angle scattering of an energetic magnetized particle by a circularly polarized electromagnetic wave

2021 ◽  
Author(s):  
Paul M. Bellan
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Wave ◽  
Kinetic Energy ◽  
Potential Energy ◽  
Pitch Angle ◽  
Energetic Electron ◽  
Circularly Polarized ◽  
Angle Scattering ◽  
Background Magnetic Field ◽  
Pseudo Potential

<p>The interaction between a circularly polarized electromagnetic wave and an energetic gyrating particle is described [1] using a relativistic pseudo-potential that is a function of the frequency mismatch,  a measure of the extent to which ω-k<sub>z</sub>v<sub>z</sub>=Ω/γ is not true. The description of this wave-particle interaction involves a sequence of relativistic transformations that ultimately demonstrate that the pseudo potential energy of a pseudo particle adds to a pseudo kinetic energy giving a total pseudo energy that is a constant of the motion. The pseudo kinetic energy is proportional to the square of the particle acceleration (compare to normal kinetic energy which is the square of a velocity) and the pseudo potential energy is a function of the mismatch and so effectively a function of the particle velocity parallel to the background magnetic field (compare to normal potential energy which is a function of position). Analysis of the pseudo-potential provides a means for interpreting particle motion in the wave in a manner analogous to the analysis of a normal particle bouncing in a conventional potential well.  The wave-particle  interaction is electromagnetic and so differs from and is more complicated than the well-known Landau damping of electrostatic waves.  The pseudo-potential profile depends on the initial mismatch, the normalized wave amplitude, and the initial angle between the wave magnetic field and the particle perpendicular velocity. For zero initial mismatch, the pseudo-potential consists of only one valley, but for finite mismatch, there can be two valleys separated by a hill. A large pitch angle scattering of the energetic electron can occur in the two-valley situation but fast scattering can also occur in a single valley. Examples relevant to magnetospheric whistler waves are discussed. Extension to the situation of a distribution of relativistic particles is presented in a companion talk [2].</p><p>[1] P. M. Bellan, Phys. Plasmas 20, Art. No. 042117 (2013)</p><p>[2] Y. D. Yoon and P. M. Bellan, JGR 125, Art. No. e2020JA027796 (2020)</p>

scholarly journals Comparison between CNA and energetic electron precipitation: simultaneous observation by Poker Flat Imaging Riometer and NOAA satellite

2005 ◽  
Vol 23 (5) ◽  
pp. 1555-1563 ◽  
Author(s):  
Y.-M. Tanaka ◽  
M. Ishii ◽  
Y. Murayama ◽  
M. Kubota ◽  
H. Mori ◽  
...  
Keyword(s):  
Pitch Angle ◽  
Electron Flux ◽  
Energetic Electron ◽  
Energetic Particles ◽  
Electron Precipitation ◽  
Angle Distribution ◽  
Pitch Angle Distribution ◽  
Loss Cone ◽  
Isotropic Pitch ◽  
Trapped Electron

Abstract. The cosmic noise absorption (CNA) is compared with the precipitating electron flux for 19 events observed in the morning sector, using the high-resolution data obtained during the conjugate observations with the imaging riometer at Poker Flat Research Range (PFRR; 65.11° N, 147.42° W), Alaska, and the low-altitude satellite, NOAA 12. We estimate the CNA, using the precipitating electron flux measured by NOAA 12, based on a theoretical model assuming an isotropic pitch angle distribution, and quantitatively compare them with the observed CNA. Focusing on the eight events with a range of variation larger than 0.4dB, three events show high correlation between the observed and estimated CNA (correlation coefficient (r0)>0.7) and five events show low correlation (r0<0.5). The estimated CNA is often smaller than the observed CNA (72% of all data for 19 events), which appears to be the main reason for the low-correlation events. We examine the assumption of isotropic pitch angle distribution by using the trapped electron flux measured at 80° zenith angle. It is shown that the CNA estimated from the trapped electron flux, assuming an isotropic pitch angle distribution, is highly correlated with the observed CNA and is often overestimated (87% of all data). The underestimate (overestimate) of CNA derived from the precipitating (trapped) electron flux can be interpreted in terms of the anisotropic pitch angle distribution similar to the loss cone distribution. These results indicate that the CNA observed with the riometer may be quantitatively explained with a model based on energetic electron precipitation, provided that the pitch angle distribution and the loss cone angle of the electrons are taken into account. Keywords. Energetic particles, precipitating – Energetic particles, trapped – Ionosphere-magnetosphere interactions

scholarly journals Distribution Functions of Type III Electrons Observed in Interplanetary Space

1980 ◽  
Vol 86 ◽  
pp. 311-313
Author(s):  
R. P. Lin ◽  
D. W. Potter ◽  
K. A. Anderson ◽  
J. Fainberg ◽  
R. G. Stone ◽  
...  
Keyword(s):  
Pitch Angle ◽  
Energetic Particle ◽  
Solar Radio ◽  
Interplanetary Space ◽  
Energetic Electron ◽  
Distribution Functions ◽  
Radio Bursts ◽  
Type Iii ◽  
Solar Type ◽  
Good Energy

We present simultaneous energetic electron and solar radio observations from the ISEE−3 spacecraft of several solar type III radio bursts. The UC Berkeley energetic particle experiment measures from 2 to ~ 103 keV with good energy and pitch angle resolution while the Meudon/GSFC radio experiment tracks type III radio bursts at 24 frequencies in the range 30 kHz—2 MHz.

Shock Drift Electron Acceleration and Pitch Angle Scattering

2001 ◽  
Vol 203 ◽  
pp. 577-579
Author(s):  
M. Vandas
Keyword(s):  
Pitch Angle ◽  
Theoretical Calculations ◽  
Electron Acceleration ◽  
Bow Shock ◽  
Interplanetary Shocks ◽  
Energetic Electrons ◽  
Angle Scattering ◽  
Earth’S Bow Shock ◽  
Additional Process

Spacecraft measurements of energetic electrons in the vicinity of the Earth's bow shock and interplanetary shocks are analyzed and compared with theoretical calculations. It is concluded that shock drift acceleration of electrons is very modified by an additional process, probably by strong pitch angle scattering. Calculations including this effect are presented.

scholarly journals Energetic electron acceleration by unsteady magnetic reconnection

2013 ◽  
Vol 9 (7) ◽  
pp. 426-430 ◽  
Author(s):  
H. S. Fu ◽  
Yu. V. Khotyaintsev ◽  
A. Vaivads ◽  
A. Retinò ◽  
M. André
Keyword(s):  
Magnetic Reconnection ◽  
Energetic Electron ◽  
Electron Acceleration

Energetic electron acceleration during magnetic reconnection

2020 ◽  
Author(s):  
Huishan Fu
Keyword(s):  
Numerical Simulations ◽  
Magnetic Reconnection ◽  
Magnetic Energy ◽  
Energetic Electron ◽  
Electron Acceleration ◽  
Particle Energy ◽  
Acceleration Process ◽  
The Earth

&lt;p&gt;During magnetic reconnection, magnetic energy is explosively converted to particle energy and consequently electrons are accelerated to hundreds of keV that are dangerous to spacecraft and astronauts. To date, how and where the acceleration happens during reconnection is still unknown. Also, how efficient can the acceleration be remains a puzzle. Using spacecraft measurements (e.g., Cluster and MMS) and numerical simulations, many attempts have been made to answer these questions during the last twenty years. In this talk, I will briefly review these progresses and then show our recent results in understanding these issues. Specifically, I will (1) report a super-efficient electron acceleration by magnetic reconnection in the Earth&amp;#8217;s magnetotail, during which electron fluxes are enhanced by 10000 times within 30 seconds; (2) discuss the mechanisms leading to super-efficient electron acceleration; (3) report the first evidence of electron acceleration at a reconnecting magnetopause, during which the acceleration process is nonadiabatic; and (4) report electron acceleration in the &lt;/p&gt;

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