Non-detection of impulsive radio signals from lightning in Martian dust storms using the radar receiver on the Mars Express spacecraft

Abstract

Here we report the results of a nearly five-year search for impulsive radio signals from lightning discharges in Martian dust storms using the radar receiver on the Mars Express spacecraft. The search covered altitudes from 275 km to 1400 km and frequencies from 4.0 to 5.5 MHz with a time resolution of 91.4 s and a detection threshold of 2.8 × 10 -18 Watts m -2 Hz -1. At comparable altitudes the intensity of terrestrial lightning is several orders of magnitude above this threshold. Although two major dust storms and many small storms occurred during the search period, no credible detections of radio signals from lightning were observed. © 2010 by the American Geophysical Union.