Response of the inner radiation belt to the violent Sun-Earth connection events of October–November 2003

Abstract

We report observations of the response of the low‐altitude radiation population below L = 3 during and after the strong solar energetic particle events and geomagnetic disturbances of late October and early November 2003, and we place this response in the context of observations throughout the 12‐year SAMPEX mission. We find that on 29 October 2003, at the approximately 600 km altitude of SAMPEX, the usual belt of energetic protons (above 19 MeV) around L = 2 almost completely disappeared, recovering only after several months. We also observed the appearance of a new belt of ultrarelativistic (above 10 MeV) electrons centered around L = 2. In the previous twelve years, we have never observed such a large decrease of the energetic protons at low altitude. An injection of very high energy electrons like this has not been seen since February 1994.