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.

Study on the variation of energetic particle pitch angle caused by NWC VLF transmitter

2020 ◽  
Author(s):  
Wei Chu ◽  
Song Xu ◽  
ZhenXia Zhang ◽  
Jianping Huang ◽  
Zhima Zeren ◽  
...  
Keyword(s):  
Pitch Angle ◽  
Energetic Particle ◽  
Electron Flux ◽  
Energetic Electron ◽  
Energetic Particles ◽  
Observation Data ◽  
Electron Loss ◽  
Loss Mechanism ◽  
Central Location ◽  
The North

&lt;p&gt;Based on the observation data collected by the Energetic Particles Detector Package(HEPP) on board CSES satellite during the period of 2018 and 2019.We analyzed the characterizes of pitch angle spectrum of energetic electron precipitated caused by NWC.&amp;#160;Our analysis revealed in details the transient properties of the space electrons induced by the man-made VLF wave emitted by the transmitter at NWC.The center location of the NWC electron flux locates in the north hemisphere other than in the south hemisphere during both quiet and disturbance period which is surprising.And the central location of NWC electron belt move westwards during the geomagnetic storm.The pitch angle distributions of the precipitation electron have the maximum flux at about 60-70 degree other than at 90 degree.The pitch angle distributions presented here are examined for evidence of the transportation mechanism&amp;#160;especially for the electron loss mechanism.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

Particle acceleration in 3D current sheets with magnetic islands: energy, density and pitch angle distributions

2021 ◽  
Author(s):  
Valentina Zharkova ◽  
Qian Xia
Keyword(s):  
Pitch Angle ◽  
Energetic Electron ◽  
High Energy ◽  
Particle Energy ◽  
Magnetic Islands ◽  
Current Sheets ◽  
Particle In Cell ◽  
Small Areas ◽  
Energy Gains ◽  
Pic Method

&lt;div&gt; &lt;div&gt; &lt;div&gt; &lt;p&gt;We will overview particle motion in 3D Harris-type RCSs without and with magnetic islands using particle-in-cell (PIC) method considering the plasma feedback to electromagnetic fields. We evaluate particle energy gains and pitch angle distributions (PADs) of accelerated particles of both changes in different locations inside current sheets as seen under the different directions by a virtual spacecraft passing through. The RCS parameters are considered comparable to heliosphere and solar wind conditions.&amp;#160;&lt;/p&gt; &lt;p&gt;The energy gains and the PADs of particles are shown to change depending on a topology of magnetic fields. &amp;#160;We report separation of electrons from ions at acceleeration in current sheets with strong guiding fields &amp;#160;and formation of transit and bounced beams from the particles of the same charge. The &amp;#160;transit particles are shown to form &amp;#160;bi-directional energetic electron beams (strahls), while bounced particles are mainly account from driopout fluxes in the heliosphere. In topologies with weak guding field strahls are mainly present inside the magneticislands and located closely above/below the X-nullpoints in the inflow regions. As the guiding field becomes larger, the regions with bi-directional strahls are compressed towards small areas in the exhausts of current sheets. Mono-directional strahls with PADS along 0 or 180 degrees are found quasi-parallel to the magnetic field lines near the X-nullpoint due to the dominant Fermi-type magnetic curvature drift acceleration. Meanwhile, high-energy electrons confined inside magnetic islands create PADs about 90&amp;#9702;.&amp;#160;&lt;/p&gt; &lt;/div&gt; &lt;/div&gt; &lt;/div&gt;

scholarly journals Survey of radiation belt energetic electron pitch angle distributions based on the Van Allen Probes MagEIS measurements

2016 ◽  
Vol 121 (2) ◽  
pp. 1078-1090 ◽  
Author(s):  
Run Shi ◽  
Danny Summers ◽  
Binbin Ni ◽  
Joseph F. Fennell ◽  
J. Bernard Blake ◽  
...  
Keyword(s):  
Pitch Angle ◽  
Radiation Belt ◽  
Energetic Electron ◽  
Van Allen Probes
Sign in / Sign up

Export Citation Format

Share Document