FIRST VLA OBSERVATION OF A SOLAR NARROW-BAND, MILLISECOND SPIKE EVENT

The first spatially resolved observation of solar, narrowband spikes i n two dimensions is presented. The 'metric' spikes around 333 MHz are classified by the broadband spectrometer Phoenix (ETH Zurich), whereas the simultaneously observing Very Large Array (VLA) provides high ang ular resolution images of the solar disc. At lower frequencies, a grou p of associated type III bursts is detected. The spikes occur at high altitude (approximate to 4.5 . 10(10) cm above the photosphere), and a t least 3 separated locations of emission can be identified. The diffe rent spike sources are separated by up to 130 '' and show different de grees of polarization. Spikes and type III bursts have the same sense of circular polarization, and according to the extrapolated potential field lines, the polarization of the different spike sources is in x-m ode. With a delay of 42 s, a thermal source appears on the same extrap olated potential field lines as the spikes at the second frequency of the VLA (1446 MHz). The location of the energy release relative to the spikes source is discussed. A scenario is proposed where the energy i s released in or near the spike source, and in which the spikes, the t ype III bursts and the thermal source originate from the same energy r elease. Hot electrons expanding along the field lines generate a type III burst (upward direction) and heat the underlying dense plasma (the rmal source).