Particle Lifetimes in Strong Diffusion.
Technical rept. Jun 73-Feb 74,
AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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The mean lifetime tau of a particle distribution, driven to isotropy by intense pitch-angle diffusion, is calculated by analytical means for conditions applicable to the earths magnetosphere. The resulting algebraic expressions reduce to tau approximately 64La35valpha sub csquared1-eta in the limit of a small equatorial loss cone half-angle alpha sub c, where v is the particle speed, L is the magnetic shell parameter, a is the radius of the earth, and eta is the particle albedo from the atmosphere at either foot of the field line. Distinction is made in the full expressions for tau between complete isotropy caused by strong pitch-angle diffusion all along the field line and incomplete isotropy caused by strong diffusion that is localized at the magnetic equator over the upward hemisphere in velocity space. Author
- Atmospheric Physics