Ignition of MHD Shocks Associated with Solar Flares

摘要: We have selected single frequency recordings of 28 ‘high-frequency’ type II bursts characterized by a starting greater than 237 MHz to estimate as accurately possible the ‘launch-time’ flare-associated MHD shocks. established time associations between metric burst onsets and characteristics microwave X-ray fluxes associated flares. The flares were impulsive events with rise times most often about 1 min in hard range 1–2 wavelength range. majority from our sample started after maximum burst. Launch shocks producing obtained using 10 × Saito coronal model shock velocities estimated at different frequencies. Back-extrapolations indicate that are launched interval prior first peak burst, probably beginning rapid increase