Magnetic Properties of Metric Noise Storms Associated with Coronal Mass Ejections

• Published in: Chinese journal of astronomy and astrophysics 2007-04, Vol.7 (2), p.265-280
• Main Authors: Wen, Ya-Yuan, Wang, Jing-Xiu, Zhang, Yu-Zong
• Format: Article
• Language: English
• Subjects: 物质抛射; 磁性质; 米波噪声爆发
• ISSN: 1009-9271
• DOI: 10.1088/1009-9271/7/2/11

Using Nancay Radioheliograph （NRH） imaging observations, combined with SOHO/Michelson Doppler Imager （MDI） magnetogram observations and coronal magnetic field extrapolation, we studied the magnetic nature of metric noise storms that are associated with coronal mass ejections （CMEs）. Four events arc selected： the events of 2000 July 14, 2001 April 26, 2002 August 16 and 2001 March 28. The identified noise storm sources cover or partially cover the active regions （ARs）, but the centers of storm sources are offset from the ARs. Using extrapolated magnetic field lines, we find that the noise storm sources trace the boundary between the open and closed field lines. We demonstrate that the disappearance of noise storm source is followed by the appearance of the burst source. The burst sources spread on the solar disk and their distributions correspond to the extent of the CME in LASCO C2 field of view. All the SOHO/Extreme Ultraviolet Imaging Telescope （EIT） dimmings associated with noise storm sources are located at the periphery of noise storms where the magnetic lines of force were previously closed and low-lying. When the closed field becomes partially or fully open, the basic configurations of noise storm sources are changed, then the noise storm sources are no longer observed. These observations provide the information that the variations of noise storms manifest the restructuring or reconfiguring of the coronal magnetic field.