scholarly journals Decimetric Type-U Solar Radio Bursts and Associated EUV Phenomena on 2011 February 9

2021 ◽  
Vol 923 (2) ◽  
pp. 268
Author(s):  
Guannan Gao ◽  
Qiangwei Cai ◽  
Shaojie Guo ◽  
Min Wang
Keyword(s):  
Numerical Simulations ◽  
Magnetic Reconnection ◽  
Solar Radio ◽  
Impulsive Phase ◽  
Generation Rate ◽  
Reconnection Rate ◽  
Solar Radio Bursts ◽  
Flare Loop ◽  
Fluctuation Amplitude ◽  
Fine Structures

Abstract A GOES M1.9 flare took place in active region AR 11153 on 2011 February 9. With a resolution of 200 kHz and a time cadence of 80 ms, the reverse-drifting (RS) type-III bursts, intermittent sequence of type-U bursts, drifting pulsation structure (DPS), and fine structures were observed by the Yunnan Observatories Solar Radio Spectrometer (YNSRS). Combined information revealed by the multiwavelength data indicated that after the DPS was observed by YNSRS, the generation rate of type-U bursts suddenly increased to 5 times what it had been. In this event, the generation rate of type-U bursts may depend on the magnetic-reconnection rate. Our observations are consistent with previous numerical simulation results. After the first plasmoid produced (plasma instability occurred), the magnetic-reconnection rate suddenly increased by 5 to 8 times. Furthermore, after the DPS, the frequency range of the turnover frequency of type-U bursts was obviously broadened to thrice what it was before, which indicates a fluctuation amplitude of the density in the loop top. Our observations also support numerical simulations during the flare-impulsive phase. Turbulence occurs at the top of the flare loop and the plasmoids can trap nonthermal particles, causing density fluctuation at the loop top. The observations are generally consistent with the results of numerical simulations, helping us to better understand the characteristics of the whole physical process of eruption.

Type II Solar Radio Bursts over Solar Cycle 21

1994 ◽  
Vol 144 ◽  
pp. 283-284
Author(s):  
G. Maris ◽  
E. Tifrea
Keyword(s):  
Solar Radio ◽  
Interplanetary Space ◽  
Impulsive Phase ◽  
Radio Bursts ◽  
Type Ii ◽  
Solar Radio Bursts ◽  
Strong Energy ◽  
Mass Ejection ◽  
Geophysical Effect ◽  
Radio Event

The type II solar radio bursts produced by a shock wave passing through the solar corona are one of the most frequently studied solar activity phenomena. The scientific interest in this type of phenomenon is due to the fact that the presence of this radio event in a solar flare is an almost certain indicator of a future geophysical effect. The origin of the shock waves which produce these bursts is not at all simple; besides the shocks which are generated as a result of a strong energy release during the impulsive phase of a flare, there are also the shocks generated by a coronal mass ejection or the shocks which appear in the interplanetary space due to the supplementary acceleration of the solar particles.

scholarly journals Separation of solar radio bursts in a complex spectrum

2010 ◽  
Vol 6 (S274) ◽  
pp. 150-152
Author(s):  
Hana Mészárosová ◽  
Ján Rybák ◽  
Marian Karlický ◽  
Karel Jiřička
Keyword(s):  
Radio Emission ◽  
Current Sheet ◽  
Solar Flares ◽  
Solar Radio ◽  
Radio Spectrum ◽  
New Method ◽  
Complex Spectrum ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Fine Structures

AbstractRadio spectra, observed during solar flares, are usually very complex (many bursts and fine structures). We have developed a new method to separate them into individual bursts and analyze them separately. The method is used in the analysis of the 0.8–2.0 GHz radio spectrum of the April 11, 2001 event, which was rich in drifting pulsating structures (DPSs). Using this method we showed that the complex radio spectrum consists of at least four DPSs separated with respect to their different frequency drifts (−115, −36, −23, and −11 MHz s−1). These DPSs indicate a presence of at least four plasmoids expected to be formed in a flaring current sheet. These plasmoids produce the radio emission on close frequencies giving thus a mixture of superimposed DPSs observed in the radio spectrum.

A Study of Solar Radio Bursts with Fine Structures during Flare/CME Events

Solar Physics ◽  
2008 ◽  
Vol 253 (1-2) ◽  
pp. 143-160 ◽  
Author(s):  
J. Huang ◽  
Y. H. Yan ◽  
Y. Y. Liu
Keyword(s):  
Solar Radio ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Fine Structures

scholarly journals Interferometric imaging with LOFAR remote baselines of the fine structures of a solar type-IIIb radio burst

2020 ◽  
Vol 639 ◽  
pp. A115
Author(s):  
PeiJin Zhang ◽  
Pietro Zucca ◽  
Sarrvesh Seethapuram Sridhar ◽  
ChuanBing Wang ◽  
Mario M. Bisi ◽  
...  
Keyword(s):  
Radio Burst ◽  
Solar Radio ◽  
Source Size ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Harmonic Emission ◽  
Apparent Source ◽  
Solar Type ◽  
Fine Structures ◽  
Source Motion

Context. Solar radio bursts originate mainly from high energy electrons accelerated in solar eruptions like solar flares, jets, and coronal mass ejections. A sub-category of solar radio bursts with short time duration may be used as a proxy to understand wave generation and propagation within the corona. Aims. Complete case studies of the source size, position, and kinematics of short term bursts are very rare due to instrumental limitations. A comprehensive multi-frequency spectroscopic and imaging study was carried out of a clear example of a solar type IIIb-III pair. Methods. In this work, the source of the radio burst was imaged with the interferometric mode, using the remote baselines of the LOw Frequency ARray (LOFAR). A detailed analysis of the fine structures in the spectrum and of the radio source motion with imaging was conducted. Results. The study shows how the fundamental and harmonic components have a significantly different source motion. The apparent source of the fundamental emission at 26.56 MHz displaces away from the solar disk center at about four times the speed of light, while the apparent source of the harmonic emission at the same frequency shows a speed of < 0.02 c. The source size of the harmonic emission observed in this case is smaller than that in previous studies, indicating the importance of the use of remote baselines.

scholarly journals Characterization of Selected Solar Radio Bursts Based on Solar Activity Detected by e-CALLISTO (Malaysia)

2014 ◽  
Vol 32 ◽  
pp. 144-154
Author(s):  
Zety Sharizat Hamidi ◽  
N.N.M. Shariff ◽  
C. Monstein
Keyword(s):  
Solar Flare ◽  
Coronal Mass Ejections ◽  
Solar Radio ◽  
Low Frequency ◽  
Weather Condition ◽  
Impulsive Phase ◽  
Primary Energy ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Solar Burst

One of the main reasons to study more about the dynamics of solar radio bursts is because solar these bursts can interfere with the Global Positioning System (GPS) and communications systems. More importantly, these bursts are a key to understand the space weather condition. Recent work on the interpretation of the low frequency region of a main solar burst is discussed. Continuum radio bursts are often related to the solar activities such as an indication of the formation of sunspot, impulsive phase of solar flares and Coronal Mass Ejections (CMEs) and their frequencies correspond to the densities supposed to exist in the primary energy release volume. Specifically, solar burst in low frequency play an important role in interpretation of Sun activities. In this work, we have selected few solar bursts that successfully detected by our station at the National Space Centre, Banting Selangor. Our objective is to correlate the solar burst with Sun activities by looking at the main sources that responsibility with the trigger of solar burst. It is found that type II burst is dominant with Coronal Mass Ejections (CMEs), type III burst associated with solar flare, IV burst with the formation of active region and type U burst high solar flare. We believed that this work is a good start to monitor Sun’s activities in Malaysia as equatorial country.

Characteristics of the fine structures in solar radio bursts at 3.2 cm

1997 ◽  
Vol 21 (3) ◽  
pp. 339-346
Author(s):  
Zhi-hai Qin ◽  
Guang-li Huang ◽  
Qi-jun Yao
Keyword(s):  
Solar Radio ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Fine Structures

scholarly journals SOLAR RADIO BURSTS WITH SPECTRAL FINE STRUCTURES IN PREFLARES

2015 ◽  
Vol 799 (1) ◽  
pp. 30 ◽  
Author(s):  
Yin Zhang ◽  
Baolin Tan ◽  
Marian Karlický ◽  
Hana Mészárosová ◽  
Jing Huang ◽  
...  
Keyword(s):  
Solar Radio ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Fine Structures

Analysis of solar radio imaging-spectroscopic observations

2020 ◽  
Author(s):  
Yihua Yan ◽  
Minghui Zhang ◽  
Zhichao Zhou ◽  
Xingyao Chen ◽  
Chengming Tan ◽  
...  
Keyword(s):  
Solar Radio ◽  
Coronal Magnetic Field ◽  
Physical Processes ◽  
Plasma Parameters ◽  
Solar Radio Bursts ◽  
Spectroscopic Observations ◽  
Beam Velocity ◽  
Radio Imaging ◽  
Multiple Frequencies ◽  
Fine Structures

&lt;p&gt;Solar radio fine structures observed in wide frequency ranges are manifestations of the physical processes related to the energy release, particle accelerations and propagations, etc. The locations of these fine structures are mostly not clear so it is important to have imaging spectroscopic observations to address these problems.&lt;/p&gt;&lt;p&gt;Mingantu Spectral Radioheliograph (MUSER) is an aperture-synthesis imaging telescope, dedicated to observe the Sun, operating on multiple frequencies in dm to cm range. The ability of MUSER allows one to diagnose coronal magnetic field and the plasma parameters such as electron beam velocity, density, spectral index, etc.&lt;/p&gt;&lt;p&gt;During 2014 to 2019, MUSER has registered a number of solar radio bursts corresponding to 2 X-class, 15 M-class, 38 C-class, 19 B-class, 4 A-class and 5 below A-class flares as well as quiet Sun observations. Here we demonstrate some interesting events from MUSER imaging-spectroscopic observations.&lt;/p&gt;

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