Ionospheric Effect of X-rays from Scorpius XR-1

Abstract

Ananthakrishnan and Ramanathan¹ recently reported observations of the field strength of 164 kHz radio waves transmitted from Tashkent, USSR, to Ahmedabad, India; they found that short-lived decreases in field strength could be correlated with transits of the X-ray source in Scorpius. The interpretation by Ananthakrishnan and Ramanathan of the correlated events is that X-radiation from Sco XR-1 ionizes the terrestrial upper atmosphere sufficiently to cause ionospheric attenuation of the radio waves. If the interpretation is correct, this would indeed be an exciting discovery with many significant ramifications for theories of nocturnal ionospheric processes. We have examined the physics of the postulated interaction between Sco XR-1 and the atmosphere in order to provide a basis for evaluating the reported interpretation.