Flare- and coronal mass ejection (CME)-associated type II bursts and related radio emissions

We report on two events that occurred within 6 hours of each other on November 3, 1997, They were observed with ground-based spectrographs in the meter to decameter range and with the WAVES experiment on the Wind spacecraft at longer wavelengths. Complementary observations were made with Extreme Ultraviolet Imaging Telescope (EIT) and Large Angle and Spectrometric Coronagraph (LASCO) experiments on the Solar and Heliospheric Observatory (SOIIO). The two events are very similar in many ways: both consist of type III bursts, type II shocks, shock-accelerated type III bursts proceeding from the type II to low frequencies, and type IV continuum. Flares and coronal mass ejections (CMEs) are associated with the two events, We trace the history of the two events from the time of the impulsive phase of the flare, which is coincident with the start time of the radio bursts and 10 to 30 min after the CME liftoff from the Sun, We derive the height-time progression of the type II shocks by using a coronal-solar wind density model and compare it with the progression of the CME in the plane of the sky, The results show that the speeds of the type II shocks in the low corona were high, 900-950 km s(-1). Then, at a height of approximate to 2 R-S, the fast shocks decelerate and become slower shocks, less than or similar to 380 km s(-1) We discuss (1) the relationship between these type II shocks, flares and CMEs, including the apparent deceleration of the type II shocks, (2) the hypotheses of blast wave versus piston-driven shocks, (3) the acceleration of electrons at the shock front producing the shock accelerated type III bursts, and (4) the acceleration of electrons that become trapped in the expanding loops of the CME and emit type IV continuum.