J. D. Perez

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

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.

Low energy particle signature of substorm dipolarization

The low energy particle signature of substorm dipolarization is exhibited through a case study of RIMS data on DE-1 at ∼2100 MLT, ILAT = 59°∼65°, L = 3.8∼5.4 RE, and geocentric distances 2.6∼2.9 RE. A strong cross-field-line, poleward outflow that lasts for a few minutes with a velocity that reaches at least 50 km/s is correlated with substorm activity evidenced in the AE index and the MAG-1 data. All the major species (H+, He+, O+) are observed to have the same bulk velocity. The parallel velocities are strongly correlated with the perpendicular velocities. The parallel acceleration is shown to result from the centrifugal force of the E×B drift induced by the dipolarizing perturbation of the magnetic field‥