Radio detection of a rapid disturbance launched by a solar flare

We report the direct observation of motion associated with a solar flare at a speed of 26,000 km s(-1). The motion is seen from a radio source at 0.33 GHz, which suddenly starts moving during the flare. At its peak, the radio source covers a quiet region of dimension 500 ". Emission from any given l ocation is sporadic. The disturbance itself does not seem to radiate, but i t excites coronal features that continue to radiate after it passes. The in ferred velocity is larger than any previously inferred velocity of a distur bance in the solar atmosphere apart from freely streaming beams of accelera ted electrons. The observed motion of the source at a fixed frequency, low polarization, and moderate bandwidth are more consistent with the typical p roperties of moving type IV radio bursts than with classical coronal shock- associated type II bursts, but any disturbance at such a high velocity must be highly supersonic and should drive a shock. We speculate that the distu rbance is associated with the realignment of magnetic fields connecting dif ferent portions of an active region.