The Statistical Analysis Of Coronal Mass Ejection-driving Shock Properties By Using The Observations Of Type ? Radio Bursts

In this thesis,we investigated 79 deca-hectometric(DH)or Metric-DH(M-DH)type-II radio burst events data observed by Learmonth,BIRS and Wind/WAVES,STEREO/SWAVES from January 2007 to December 2015.Using the coronal density model assumption and frequency-time drift evolution to perform shock height time fitting,the corresponding shock speed is deduced,and the shock parameters and Coronal Mass Ejection(CME),solar flares and solar energetic particles(Solar Energetic Particle,SEP)and other parameters,and the change law,and discussed the impact of radio enhancement on these relationships and its role in studying particle acceleration.The results were found as follows:(1)In general,at the onset time of type ? radio bursts within M-DH and DH waveband,the shock front is about 0.4Rs ahead of the leading edge of CME(shock standoff distance),and this distance increases as the CME propagates outward.In the low and high corona,the relationship between shock standoff distance and CME speed indicates a significant difference;At lower altitudes,the faster the CME speed,the greater the shock standoff distance,while at higher altitudes,the slower the CME speed,the greater the standoff distance.(2)Comparing with the events with no radio enhancement,the correlation coefficient between the shock speed and the mass and kinetic energy of the associated CME is significantly high for the events with radio enhancement.There is no correlation between the duration of type ? radio burst in M-DH waveband with enhancement and the speed?mass and kinetic energy of CME.However,it presents a positive a positive correlation for the events with no radio enhancement.The CME speed?mass?kinetic energy and flare class with respect to type ? radio enhancement events were generally higher than that of no enhancement events.the absence height of enhancement events are also distinctly higher than that non-enhancement events,which reveals that the enhanced CME shock characterized by enhanced radio burst can keep propagating to more higher or further space;the proportion of SEP events generated by radio enhancement events is slightly higher than that of no radio enhancement events(73.5%> 67.4 %),but the ratio of radio enhancement events to large SEPevents(67.6%)was significantly higher than that of radio enhancement events(37.2%).(3)Usually the speed of shock that can produce SEP event is obviously higher than that with producing no SEP event;Whether radio enhancement or not,the onset height of type ?s associated with SEP event is slightly lower than that of event without SEP.The CME speed?mass and kinetic energy with respect to SEP events are significantly greater than those of no SEP events,For the absence height,the SEP events are significantly higher than the no-SEP events.(4)As shown in the characteristic time analysis,the initial release time of SEPs is generally earlier than the start time of radio enhancement,so we can the radio enhancement is only as a signature of the shock enhancement rather than the direct generator of SEP events.When one fast and wide CME fully sweeps over another slow and narrow preceding CME,CME interaction can more easily generate radio enhancement,but no distinctive difference between SEP events and non-SEP events.The results in this thesis showed that the shock speed obtained from type ? radio burst inversion is normally equivalent to the CME speed,and the shock height is slightly higher than the CME height,which is linear with the CME-driven shock model;the CME with radio enhancement has higher speed?mass and kinetic energy,can drive shock waves to a higher altitude and have a higher probability of SEP generation,but radio enhancement is only an enhanced performance of CME shock waves interacting with other CMEs.Enhanced shock waves may enhance particle acceleration process which can make it easier to produce large SEP event.However,radio enhancement is not the direct cause of SEP events.CME-diven shock that produce SEP event tends to start at lower altitude and propagate up to higher altitude with longer duration.