Statistics and Classification of the Microwave Zebra Patterns Associated with Solar Flares |
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Baolin Tan Submitted: 2014-07-10 18:50
The microwave zebra pattern (ZP) is the most interesting, intriguing, and complex spectral structure frequently observed in solar flares. A comprehensive statistical study will certainly help us to understand the formation mechanism, which is not exactly clear now. This work presents a comprehensive statistical analysis on a big sample with 202 ZP events collected from observations at the Chinese Solar Broadband Radio Spectrometer at Huairou and the Ondřejov; Radiospectrograph in Czech Republic at frequencies of 1.00 - 7.60 GHz during 2000 - 2013. After investigating the parameter properties of ZPs, such as the occurrence in flare phase, frequency range, polarization degree, duration, etc., we find that the variation of zebra stripe frequency separation with respect to frequency is the best indicator for a physical classification of ZPs. Microwave ZPs can be classified into 3 types: equidistant ZP, variable-distant ZP, and growing-distant ZP, possibly corresponding to mechanisms of Bernstein wave model, whistler wave model, and double plasma resonance model, respectively. This statistical classification may help us to clarify the controversies between the existing various theoretical models, and understand the physical processes in the source regions.
Authors: Baolin Tan, Chengming Tan, Yin Zhang, H. Meszarosova, M. Karlický
Projects: None
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Publication Status: ApJ, 2014, 780, 129
Last Modified: 2014-07-11 14:34
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New Aspects on Particle Acceleration in Solar Flares from RHESSI Observations |
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Baolin Tan Submitted: 2008-06-19 20:22
From the observations with the Chinese Solar Broadband
Radiospectrometer (SBRS/Huairou) in the frequency range of 1.10 - 2.06 GHz and 2.60 - 3.80 GHz during 2004 - 2006, we select 14 flare events which were associated with numerous fast microwave sub-second pulsating structures (period: P<0.5 s). In order to describe these sub-second pulsating structures comprehensively, we defined a set of observable parameters including emission frequency (f0), bandwidth (bw), polarization degree (r), period (P), duration(D), modulation depth (M), quality factor (Q), single pulse frequency drifting rate (Rspfd), global frequency drifting rate (Rgfd), and symmetrical factor of the pulse profile (S). Then based on a detailed analysis of the spectrograms of the fast pulsations which occurred in one of these flares (an X3.4 flare/CME event occurred on 13 Dec. 2006), we discuss the possible relations among these observable parameters and their physical implications for the dynamical processes of solar eruptive events, and applied them to interpret the nature of the pulsations in the flare/CME event. Such study of microwave periodic pulsations provide us a useful tool to probe the details of the flare kernels, and understand the physical mechanism of solar eruptive processes.
Authors: Baolin Tan
Projects: None
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Publication Status: accepted by Solar Physics, DOI:10.1007/s11207-008-9235-3
Last Modified: 2008-09-23 20:59
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Subject will be restored when possible |
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Baolin Tan Submitted: 2008-06-12 20:13
From the observations with the Chinese Solar Broadband Radiospectrometer (SBRS/Huairou) in the frequency range of 1.10 - 2.06 GHz and 2.60 - 3.80 GHz during 2004 - 2006, we select 14 flare events which were associated with numerous fast microwave sub-second pulsating structures (period: P<0.5 s). In order to describe these sub-second pulsating structures comprehensively, we defined a set of observable parameters including emission frequency (f0), bandwidth (bw), polarization degree (r), period (P), duration (D), modulation depth (M), quality factor (Q), single pulse frequency drifting rate (Rspfd), global frequency drifting rate (Rgfd), and symmetrical factor of the pulse profile (S). Then based on a detailed analysis of the spectrograms of the fast pulsations which occurred in one of these flares (an X3.4 flare/CME event occurred on 13 Dec. 2006), we discuss the possible relations among these observable parameters and their physical implications for the dynamical processes of solar eruptive events, and applied them to interpret the nature of the pulsations in the flare/CME event. Such study of microwave periodic pulsations provide us a useful tool to probe the details of the flare kernels, and understand the physical mechanism of solar eruptive processes.
Authors: Baolin Tan
Projects: None
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Publication Status: accepted, DOI: 10.1007/s11207-008-9235-3
Last Modified: 2008-06-13 06:53
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Subject will be restored when possible |
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Baolin Tan Submitted: 2008-06-12 20:13
From the observations with the Chinese Solar Broadband Radiospectrometer (SBRS/Huairou) in the frequency range of 1.10 - 2.06 GHz and 2.60 - 3.80 GHz during 2004 - 2006, we select 14 flare events which were associated with numerous fast microwave sub-second pulsating structures (period: P<0.5 s). In order to describe these sub-second pulsating structures comprehensively, we defined a set of observable parameters including emission frequency (f0), bandwidth (bw), polarization degree (r), period (P), duration (D), modulation depth (M), quality factor (Q), single pulse frequency drifting rate (Rspfd), global frequency drifting rate (Rgfd), and symmetrical factor of the pulse profile (S). Then based on a detailed analysis of the spectrograms of the fast pulsations which occurred in one of these flares (an X3.4 flare/CME event occurred on 13 Dec. 2006), we discuss the possible relations among these observable parameters and their physical implications for the dynamical processes of solar eruptive events, and applied them to interpret the nature of the pulsations in the flare/CME event. Such study of microwave periodic pulsations provide us a useful tool to probe the details of the flare kernels, and understand the physical mechanism of solar eruptive processes.
Authors: Baolin Tan
Projects:
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Publication Status: accepted by Solar Physics, DOI: 10.1007/s11207-008-9235-3
Last Modified: 2008-09-23 20:59
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