A shock associated (SA) radio event and related phenomena observed from the base of the solar corona to 1 AU

Abstract

We present for the first time an almost complete frequency coverage of a Shock Associated (SA) radio event and related phenomena observed on May 6, 1996 at 9:27 UT. It is observed from the base of the solar corona up to almost 1 Astronomical Unit (AU) from the Sun by the following radio astronomical instruments: the Ondřejov spectrometer operating between 4.5 GHz and 1 GHz (radiation produced near the chromosphere); the Thermopyles Artemis‐IV spectrograph operating between 600 MHz and 110 MHz (distance range about 1.1–1.4 R ⊙ from sun center); the Nançay Decameter Array operating between 75 and 25 MHz (distance range about 1.4–2 R ⊙ ); and the RAD2 and RAD1 radio receivers on the WIND spacecraft covering the range from 14 MHz to about 20 kHz (distance range between 3 R ⊙ and about 1 AU). Observations at the Nançay Decameter Array clearly show that the SA event starts from a coronal type II radio burst which traces the progression of a shock wave through the corona above 1.8 R ⊙ –2 R ⊙ from the sun center. This SA event has no associated radio emission in the decimetric‐metric range, thus there is no evidence for electron injection in the low/middle corona.