S-bands of Jovian decametric emission

¹ Institute of Radio Astronomy, National Academy of Sciences of Ukraine, Chervonopraporna 4, 61002 Kharkiv, Ukraine e-mail: rai@ri.kharkov.ua
² Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042 Graz, Austria e-mail: rucker@oeaw.ac.at

Received: 2 November 2007
Accepted: 1 February 2008

Abstract

There are theoretical and experimental arguments for a modulation of Jovian decametric S-emission by standing Alfvén waves in the regions of radio sources. One effect of such modulation is the concentration of S-burst emission around certain frequencies (S-bands) in dynamic spectra of radio emission. It is argued that S-bands are generated at the local electron cyclotron frequencies, around nodes of a standing Alfvén wave. To test this hypothesis, we derived several verifiable predictions: the anti-correlation of radio-flux in adjacent S-bands at short time scales (<0.1 s); the correlation of frequency shifts of S-bands at long time scales (>0.1 s); and the transformation of the broadband S-storm into S-bands. We searched for and found these effects experimentally. Because the predictions are confirmed, the standing wave modulation of Jovian S-emission appears valid.