Comparing high energy electron precipitation from radiation belt models to satellite observations
Abstract
Particle precipitation is one of the loss mechanisms from the Earth's Radiation Belts whereby particles trapped by the Earth's magnetic field are scattered into the loss cone due to wave-particle interactions. Energetic electron precipitation is known to create ozone destroying chemicals which can affect the temperatures of the polar regions therefore, it is crucial to be able to accurately quantify this input to determine the effect of space weather on the Earth's atmosphere. Based on a previously published work, we calculate the magnetic local time (MLT) dependent electron precipitation using bounce-averaged pitch angle diffusion coefficents for chorus, plasmaspheric hiss and EMIC waves, and atmospheric collisions. We compare this MLT-dependent electron precipitation to the electron precipitation calculated by the British Antarctic Survey Radiation Belt Model (BAS-RBM) for the March 2013 storms. The BAS-RBM solves a 3D Fokker-Plank diffusion equation with a set of drift averaged diffusion coefficients that characterise the wave-particle interactions and atmospheric collisions, and also includes the effect of radial transport. We find at L* = 4 for 300 keV electrons, the flux in the loss cone is dominated by the chorus waves whereas for 1 MeV electrons, both chorus and plasmaspheric hiss are important. In order to compare with data from the Polar Orbiting Environmental Satellite (POES), we converted the MLT-dependent electron precipitation to an integral flux to compare to the >300 keV electron channel. We have also compared the counts measured by the 6th proton (P6) channel which measures electrons when the proton flux is low (as the electrons contaminate this channel). We find the MLT-dependent calculation based on the diffusion coefficents reproduces the occurrence of the electron precipitation measured by POES but with some significant differences. We discuss the origin of these differences and ways to improve the model.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSA24B..03R
- Keywords:
-
- 0341 Middle atmosphere: constituent transport and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 3334 Middle atmosphere dynamics;
- ATMOSPHERIC PROCESSES;
- 2716 Energetic particles: precipitating;
- MAGNETOSPHERIC PHYSICS;
- 2788 Magnetic storms and substorms;
- MAGNETOSPHERIC PHYSICS