FINE STRUCTURE EVENTS IN MICROWAVE EMISSION DURING SOLAR MINIMUM
Journal Title: Solar-Terrestrial Physics - Year 2019, Vol 5, Issue 2
Abstract
The solar minimum is a period with a relatively smaller number of sunspots and solar eruptions, and has been less studied before. Since the radio signal rapidly responds to the change of solar plasma and magnetic field, we perform a comprehensive analysis of high resolution spectrum data from SBRS and MUSER: 1) a search for solar radio bursts of different kinds in recent solar minima (2007–2009 and 2016–2018); 2) an analysis of several typical radio burst events, negative and positive drifting bursts, for example the November 22, 2015 and August 29, 2016 events; superfine spectral structure events with mini-flares and even without sunspots, for example the March 28, 2008 and July 04, 2017 events. These results show that there were many radio bursts with a fine structure during solar minima. These events occurred not only in powerful flares, but also in faint flares (class C and B by GOES) or even without flares, but in regions related to weak brightenings or ejecta. We assume that the weak solar radio bursts observed by telescopes with high sensitivity and low interference will help us to understand the basic physical characteristics of small-scale solar eruptions.
Authors and Affiliations
Chengming T. , Baolin T. , Yihua Y. , Wei W. , Linjie C. , Fei L. , Yujiang D.
MEASUREMENT OF ENERGY DISTRIBUTION FOR LOW POWER NANOFLARES
We propose a method to measure the energy distribution of low-energy flares (nanoflares) in the energy range below 1023 erg. As an example, we measured the spectrum of nanoflares in the 1021–1026 erg range for two Sun’s...
SECOND-ORDER PERTURBATIONS IN ALFVÉN WAVES IN FINITE PRESSURE PLASMA
It is shown first that in finite pressure plasma, just as in cold plasma, Alfvén waves created by an initial perturbation generate plasma flows and decreases in the magnetic field, which propagate along with these waves....
THE CURRENT STATE OF THE THEORY OF PC1 RANGE ULF PULSATIONS IN MAGNETOSPHERIC PLASMA WITH HEAVY IONS: A REVIEW
The review considers the current state of the theory of short-period ULF waves in plasma with admixture of heavy ions (ions whose mass significantly exceeds the mass of protons). The presence of heavy ions influences the...
LONG-TERM SOLAR FLUX OBSERVATIONS WITH IRKUTSK INCOHERENT SCATTER RADAR (IISR) IN 2011–2019
Irkutsk incoherent scatter radar (IISR) is an oblongish horn antenna that operates in a meter waveband (154–162 MHz), has a 0.5°×20° beam, and a frequency steering allowing us to tilt the beam by 30° to the south. Beside...
ON THE GROUP VELOCITY OF WHISTLING ATMOSPHERICS
The dynamic spectrum of a whistling atmospheric is a signal of falling tone, and the group delay time of the signal as a function of frequency is formed as a result of propagation of a broadband pulse in a medium (magnet...