DIAGNOSTICS ON THE SOURCE PROPERTIES OF A TYPE II RADIO BURST WITH SPECTRAL BUMPS

In recent studies, we proposed that source properties of type II radio bursts can be inferred through a causal relationship between the special shape of the type II dynamic spectrum (e. g., bump or break) and simultaneous extreme ultraviolet (EUV)/white light imaging observations (e. g., CME-shock crossing streamer structures). As a further extension of these studies, in this paper we examine the coronal mass ejection (CME) event on 2007 December 31 associated with a multiple type II radio burst. We identify the presence of two spectral bump features on the observed dynamic spectrum. By combining observational analyses of the radio spectral observations and the EUV-white light imaging data, we conclude that the two spectral bumps result from a CME-shock propagating across dense streamers on the southern and northern sides of the CME. It is inferred that the corresponding two type II emissions originate separately from the two CME-shock flanks where the shock geometries are likely quasi-perpendicular or oblique. Since the emission lanes are bumped as a whole within a relatively short time, it suggests that the type II radio bursts with bumps of this study are emitted from spatially confined sources (with a projected lateral dimension smaller than 0.05-0.1 R-circle dot at a fundamental frequency level of 20-30 MHz).

[1]  J. Gosling.  The solar flare myth , 1993 .

[2]  D. J. Mclean,et al.  Type II Solar Radio Bursts Observed with the Culgoora Radioheliograph during a Flare on 17 June 1968 , 1968, Publications of the Astronomical Society of Australia.

[3]  L. Ball,et al.  Shock Drift Acceleration of Electrons , 2001, Publications of the Astronomical Society of Australia.

[4]  J. Luhmann,et al.  RELATIONSHIP BETWEEN A CORONAL MASS EJECTION-DRIVEN SHOCK AND A CORONAL METRIC TYPE II BURST , 2009 .

[5]  A. D. Lago,et al.  CORONAL MASS EJECTION DYNAMICS REGARDING RADIAL AND EXPANSION SPEEDS , 2011 .

[6]  G. Holman,et al.  Solar type II radio emission and the shock drift acceleration of electrons , 1983 .

[7]  J. Vial,et al.  LARGE-SCALE EXTREME-ULTRAVIOLET DISTURBANCES ASSOCIATED WITH A LIMB CORONAL MASS EJECTION , 2010 .

[8]  I. Cairns,et al.  Type II radio bursts: 1. New entirely analytic formalism for the electron beams, Langmuir waves, and radio emission , 2012 .

[9]  Y. Moon,et al.  Low coronal observations of metric type II associated CMEs by MLSO coronameters , 2008 .

[10]  Y. Moon,et al.  Relationship between multiple type II solar radio bursts and CME observed by STEREO/SECCHI , 2011 .

[11]  J. Davila,et al.  THREE-DIMENSIONAL POLARIMETRIC CORONAL MASS EJECTION LOCALIZATION TESTED THROUGH TRIANGULATION , 2010 .

[12]  C. Wu.  A fast Fermi process: Energetic electrons accelerated by a nearly perpendicular bow shock , 1984 .

[13]  N. Gopalswamy,et al.  Origin of coronal and interplanetary shocks: A new look with Wind spacecraft data , 1998 .

[14]  G. Dulk,et al.  Radio Emission from the Sun and Stars , 1985 .

[15]  J. Wild.  Some Investigations of the Solar Corona: The First Two Years of Observation With the Culgoora Radioheliograph , 1970, Publications of the Astronomical Society of Australia.

[16]  J. Pomoell,et al.  CME liftoff with high-frequency fragmented type II burst emission , 2008, 0809.0405.

[17]  A. Klassen,et al.  Catalogue of solar type II radio bursts observed from September 1990 to December 1993 and their statistical analysis. , 1996 .

[18]  J. Raymond,et al.  Coronal transients and metric type II radio bursts. I. Effects of geometry , 2004 .

[19]  F. Guo,et al.  A BROKEN SOLAR TYPE II RADIO BURST INDUCED BY A CORONAL SHOCK PROPAGATING ACROSS THE STREAMER BOUNDARY , 2012, 1203.1511.

[20]  Y. Moon,et al.  A study of CME and type II shock kinematics based on coronal density measurement , 2007 .

[21]  K. Sheridan,et al.  A Study of Multiple Type II Solar Radio Events , 1982, Publications of the Astronomical Society of Australia.

[22]  G. Petrie,et al.  CORONAL MASS EJECTIONS AND GLOBAL CORONAL MAGNETIC FIELD RECONFIGURATION , 2009 .

[23]  R. Decker.  Particle acceleration at shocks with surface ripples , 1990 .

[24]  F. Guo,et al.  THE EFFECT OF LARGE-SCALE MAGNETIC TURBULENCE ON THE ACCELERATION OF ELECTRONS BY PERPENDICULAR COLLISIONLESS SHOCKS , 2009, 1003.5946.

[25]  W. Erickson,et al.  Solar Type II Radio Bursts and IP Type II Events , 2005 .

[26]  W. Erickson.  The Bruny Island Radio Spectrometer , 1997, Publications of the Astronomical Society of Australia.

[27]  P. Robinson,et al.  Type II solar radio bursts: 2. Detailed comparison of theory with observations , 2012 .

[28]  P. Gallagher,et al.  Investigating the driving mechanisms of coronal mass ejections , 2010, 1003.5035.

[29]  Dusan Odstrcil,et al.  Numerical simulation of the 12 May 1997 interplanetary CME event , 2004 .

[30]  J. P. Wild,et al.  Radio Bursts from the Solar Corona , 1972 .

[31]  Y. Liu,et al.  Radio signatures of CME-streamer interaction and source diagnostics of type II radio burst , 2012, 1204.5569.

[32]  Nicole Vilmer,et al.  Sixty-five years of solar radioastronomy: flares, coronal mass ejections and Sun–Earth connection , 2008 .

[33]  Gordon Newkirk.  The Solar Corona in Active Regions and the Thermal Origin of the Slowly Varying Component of Solar Radio Radiation. , 1961 .

[34]  P. Riley,et al.  Kinematic Treatment of Coronal Mass Ejection Evolution in the Solar Wind , 2004 .

[35]  S. Wu,et al.  Direct Detection of a Coronal Mass Ejection-Associated Shock in Large Angle and Spectrometric Coronagraph Experiment White-Light Images , 2003 .

[36]  N. Sheeley,et al.  Detection of coronal mass ejection associated shock waves in the outer corona , 2000 .

[37]  S. Knock,et al.  Type II radio emission predictions: Sources of coronal and interplanetary spectral structure , 2005 .

[38]  A. Vourlidas,et al.  Constraints on Coronal Mass Ejection Dynamics from Simultaneous Radio and White-Light Observations , 2003 .