Microwave Emission of Solar Flares: Coronal Mass Ejections and Shock Waves

Abstract

ABSTRACT. Coronal mass ejections (CMEs) mostly affect the geomagnetic field. These structures are observed and studied with coronagraphic images therefore we don't see the corona in the plane of the sky and the measurements of the propagation speed for solar disk events are not accessible to coronagraphic observations. This suggests that microwave emission of solar flares that can be attributed to the gyrosynchrotron mechanism of mildly relativistic electrons can be used. In turn, the relationship between coronal shock waves and CMEs also remains unclear.The data set that we use in this study is based on microwave (μ) observations of spectral fluxes F μ at 8.8 GHz obtained with the Radio Solar Telescope Network for the 124 proton solar events . The correlation coefficient r between the CME velocities V CME and integral fluxes of microwave emission ∫F μ dt achieves of about 0.8 while it does not exceed 0.36 between V CME and the shock wave velocities. It has been found the quite strong correlation between the growth rate of microwave emission and the deceleration of frequency drift in the frequency range of 25-180 GHz (r ≈ 0.66). The obtained results suggest that microwave observation can be used to predict V CME and the shock wave generation occurs in the region of flare energy release.

Solar Microwave Emission Associated with Coronal Mass Ejections (CME)

“…The estimation of CME magnetic fields can be diagnostic based on radio observations [3], [4]. Connection between CMEs and solar radio events has been studied earlier.…”

Relationship of the Proton Flux Intensity With Relative Distance Between Harmonics of Type Ii Radio Bursts in the Range 25-180 Мhz

“…As can be seen, two bands can be distinguished corresponding to the main and second harmonics. In this work, we used a new regression model (Isaeva and Tsap, 2017) to approximate the type II burst harmonics (1), where fi,j is the frequency of the maximum of type II burst at a given harmonic at a given time ti, ireference number, j -harmonic number, aj and dj -linear regression coefficients. c) The relationship between the proton flux intensity Ip and the frequency fi,1, min, at which the minimum value of the relative distance bi,min between the harmonics of the type II burst is observed.…”

The Relationship of the SCR With Parameters of Radio Bursts and Cme

“…Almost all proton events are accompanied by coronal mass ejections (CME). Earlier in the work (Isaeva & Tsap, 2017) it was shown that there is a strong relationship between the speed of the CME V CME and the integral flux of the continuum microwave bursts ∫F μ dt. Moreover, the connection between the speed of the CME and the integral flux of the continual radio bursts of the IV type weakens with a decrease in the frequency of the burst of the IV type and is practically absent already in the meter-decameter range.…”