Initial ion equatorial pitch angle distributions from medium and high energy neutral atom images obtained by IMAGE

Abstract

Examples of the extraction of equatorial ion pitch angle distributions from energetic neutral atom images taken by the HENA instrument on June 10, 2000 between 1200 and 1600 UT and MENA on August 12, 2000 at about 1000 UT on board the IMAGE satellite are presented. The extraction is performed using a method of deconvolution that expands the unknown equatorial ion pitch angle distribution in terms of tri‐cubic splines, and then finds the expansion coefficients by requiring that the result fit the data and be as smooth as possible.