CORRELATION BETWEEN THE ONSET TIMES OF CMES AND TYPE III RADIO BURSTS

摘要

We present a possibility to estimate the projection effects on CME measurements. We assume that (1) high energy electrons are produced at the shock front ahead of the CME, and (2) the radio burst starts when the shock reaches open field lines (～ 3R_☉). In other words, the onset time of the radio burst corresponds to the time when the CME leading edge reaches 3R_☉ is well known coronographic observations of halo CMEs are subject to projection effects. Fortunately, the Wind/WAVES observations of type III radio bursts associated with shock waves are free from projection effects. The difference between the onset times of CMEs and radio bursts should be strongly correlated with the position of CMEs on the Sun. We try to determine this correlation for CMEs during maximum of solar activity.