scholarly journals Comparing Electron Precipitation Fluxes Calculated From Pitch Angle Diffusion Coefficients to LEO Satellite Observations

2021 ◽  
Vol 126 (3) ◽  
Author(s):  
J. A. Reidy ◽  
R. B. Horne ◽  
S. A. Glauert ◽  
M. A. Clilverd ◽  
N. P. Meredith ◽  
...  
Keyword(s):  
Diffusion Coefficients ◽  
Pitch Angle ◽  
Satellite Observations ◽  
Electron Precipitation ◽  
Leo Satellite

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 Relativistic electron dropouts by pitch angle scattering in the geomagnetic tail

2006 ◽  
Vol 24 (11) ◽  
pp. 3151-3159 ◽  
Author(s):  
J. J. Lee ◽  
G. K. Parks ◽  
K. W. Min ◽  
M. P. McCarthy ◽  
E. S. Lee ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Relativistic Electron ◽  
Magnetic Moment ◽  
Pitch Angle ◽  
Electron Flux ◽  
Electron Precipitation ◽  
Precipitation Event ◽  
Real Field ◽  
Geomagnetic Tail ◽  
Angle Scattering

Abstract. Relativistic electron dropout (RED) events are characterized by fast electron flux decrease at the geostationary orbit. It is known that the main loss process is non adiabatic and more effective for the high energy particles. RED events generally start to occur at midnight sector and propagate to noon sector and are correlated with magnetic field stretching. In this paper, we discuss this kind of event can be caused from pitch angle diffusion induced when the gyro radius of the electrons is comparable to the radius of curvature of the magnetic field and the magnetic moment is not conserved any more. While this process has been studied theoretically, the question is whether electron precipitation could be explained with this process for the real field configuration. This paper will show that this process can successfully explain the precipitation that occurred on 14 June 2004 observed by the low-altitude (680 km) polar orbiting Korean satellite, STSAT-1. In this precipitation event, the energy dispersion showed higher energy electron precipitation occurred at lower L values. This feature is a good indicator that precipitation was caused by the magnetic moment scattering in the geomagnetic tail. This interpretation is supported by the geosynchronous satellite GOES observations that showed significant magnetic field distortion occurred on the night side accompanying the electron flux depletion. Tsyganenko-01 model also shows the magnetic moment scattering could occur under the geomagnetic conditions existing at that time. We suggest the pitch angle scattering by field curvature violating the first adiabatic invariant as a possible candidate for loss mechanism of relativistic electrons in radiation belt.

scholarly journals Radiation belt electron precipitation due to VLF transmitters: Satellite observations

2008 ◽  
Vol 35 (9) ◽  
Author(s):  
J.-A. Sauvaud ◽  
R. Maggiolo ◽  
C. Jacquey ◽  
M. Parrot ◽  
J.-J. Berthelier ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Satellite Observations ◽  
Electron Precipitation

scholarly journals Pitch angle distribution of trapped energetic protons and helium isotope nuclei measured along the Resurs-01 No. 4 LEO satellite

2005 ◽  
Vol 23 (9) ◽  
pp. 2983-2987 ◽  
Author(s):  
A. Leonov ◽  
M. Cyamukungu ◽  
J. Cabrera ◽  
P. Leleux ◽  
J. Lemaire ◽  
...  
Keyword(s):  
Pitch Angle ◽  
Helium Isotope ◽  
Helium Isotopes ◽  
Angle Distribution ◽  
Strip Detectors ◽  
Direct Measurements ◽  
He Isotopes ◽  
Silicon Strip Detectors ◽  
Leo Satellite ◽  
Momentum Direction

Abstract. The NINA detector on board the Resurs-01 No. 4 satellite (835 km, 98° inclination) is equipped with particle trackers based on silicon strip detectors. From the energy deposited in each of its silicon layers the mass, the momentum direction and energy of incident particles have been determined. The resolutions in mass and energy allow identification of H and He isotopes over the 10-50 MeV/n energy range. The angular resolution is about 2.5°. We present the direct measurements of proton and helium isotopes pitch angle distributions derived from Resurs-01 No.4/NINA observations and their variations as functions of (B, L) coordinates and energy. The measurements of trapped helium isotopes spectrum are also presented.

PSE MORPHOLOGY AND MEDIUM LATITUDE RADIATION BELT ELECTRON PITCH-ANGLE DIFFUSION COEFFICIENTS: A TEST OF THE PSE-MODEL

1979 ◽  
pp. 351-356 ◽  
Author(s):  
E.A. Lauter ◽  
A. Grafe ◽  
B. Nikutowski ◽  
J. Taubenheim ◽  
R. Treumann ◽  
...  
Keyword(s):  
Diffusion Coefficients ◽  
Pitch Angle ◽  
Radiation Belt

Unmagnetized diffusion for azimuthally symmetric wave and particle distributions

1988 ◽  
Vol 40 (1) ◽  
pp. 179-198 ◽  
Author(s):  
P. B. Dusenbery ◽  
L. R. Lyons
Keyword(s):  
Magnetic Field ◽  
Diffusion Coefficients ◽  
Pitch Angle ◽  
Particle Distribution ◽  
Ion Beam ◽  
Distribution Model ◽  
Sound Waves ◽  
Linear Diffusion ◽  
Particle Distributions ◽  
Diffusion Rates

The general equations describing the quasi-linear diffusion of charged particles from resonant interactions with a spectrum of electrostatic waves are given, assuming the wave and particle distributions to be azimuthally symmetric. These equations apply when a magnetic field organizes the wave and particle distributions in space, but when the local interaction between the waves and particles can be evaluated assuming that no magnetic field is present. Such diffusion is, in general, two-dimensional and is similar to magnetized diffusion. The connection between the two types of diffusion is presented. In order to apply the general quasi-linear diffusion coefficients in pitch angle and speed, a specific particle-distribution model is assumed. An expression for the unmagnetized dielectric function is derived and evaluated for the assumed particle distribution model. It is found that slow-mode ion-sound waves are unstable for the range of plasma parameters considered. A qualitative interpretation of unmagnetized diffusion is presented. The diffusion coefficients are then evaluated for resonant ion interactions with ion-sound waves. The results illustrate how resonant ion diffusion rates vary with pitch angle and speed, and how the diffusion rates depend upon the distribution of wave energy in k–space. The results of this study have relevance for ion beam heating in the plasma-sheet boundary layer and upstream of the earth's bow shock.

Banded structures in electron pitch angle diffusion coefficients from resonant wave-particle interactions

2016 ◽  
Vol 23 (4) ◽  
pp. 042101 ◽  
Author(s):  
A. K. Tripathi ◽  
R. P. Singhal ◽  
G. V. Khazanov ◽  
L. A. Avanov
Keyword(s):  
Diffusion Coefficients ◽  
Pitch Angle ◽  
Particle Interactions ◽  
Resonant Wave ◽  
Wave Particle Interactions
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