Low-altitude measurements of 2-6 MeV electron trapping lifetimes at 1.5 ≤ L ≤ 2.5

During the Halloween Storm period ( October November 2003), a new Van Allen belt electron population was powerfully accelerated. The inner belt of electrons formed in this process decayed over a period of days to years. We have examined quantitatively the decay rates for electrons seen in the region of 1.5 <= L <= 2.5 using SAMPEX satellite observations. At L = 1.5 the e- folding lifetime for 2 - 6 MeV electrons was tau similar to 180 days. On the other hand, for the half- dozen distinct acceleration ( or enhancement) events seen during late- 2003 through 2005 at L similar to 2.0, the lifetimes ranged from tau similar to 8 days to tau similar to 35 days. We compare these loss rates to those expected from prior studies. We find that lifetimes at L = 2.0 are much shorter than the average 100 - 200 days that present theoretical estimates would suggest for the overall L = 2 electron population. Additional wave- particle interaction aspects must be included in theoretical treatments and we describe such possibilities here.