Spatial analysis of solar type III events associated with narrow band spikes at metric wavelengths

The spatial association of narrow band metric radio spikes with type III bu rsts is analyzed. The analysis addresses the question of a possible causal relation between the spike emission and the acceleration of the energetic e lectrons causing the type III burst. The spikes are identified by the Phoen ix-2 spectrometer (ETH Zurich) from survey solar observations in the freque ncy range from 220 MHz to 530 MHz. Simultaneous spatial information was pro vided by the Nancay Radioheliograph (NRH) at several frequencies. Five even ts were selected showing spikes at one or two and type III bursts at two or more Nancay frequencies. The 3-dimensional geometry of the single events h as been reconstructed by applying different coronal density models. As a wo rking hypothesis it is assumed that emission at the plasma frequency or its harmonic is the responsible radiation process for the spikes as well as fo r the type III bursts. It has been found that the spike source location is consistent with the backward extrapolation of the trajectory of the type II I bursts, tracing a magnetic field line. In one of the analyzed events, typ e III bursts with two different trajectories originating from the same spik e source could be identified. These findings support the hypothesis that na rrow band metric spikes are closely related to the acceleration region.