NRAO: National Radio Astronomy Observatory

About this Image

A coronal mass ejection (CME) is the mass ejected from the Sun due to a solar flare. CMEs are recognized as primary drivers of disturbances in the interplanetary medium. As such, they can have a profound impact on the near-Earth environment. A long-standing problem has been understanding the origin of CMEs and the details of their relationship to a number of associated phenomena, including solar flares, coronal and interplanetary type II radio bursts, shocks, and solar energetic particle (SEP) events. This image shows the first time the expanding CME loops have been imaged directly at radio wavelengths. The image is a snapshot map of the radio CME at a frequency of 164 MHz at the time of maximum flux. The background emission from the Sun has been subtracted. Time variable radio emission from a noise storm is present to the northwest. The radio CME is visible as a complex ensemble of loops extended out to the southwest. Also shown is the spectral index measured at four locations in the radio CME. The radio-emitting CME loops are most likely the result of synchrotron emission from energetic electrons interacting with magnetic fields.

Investigator(s):  Tim Bastian, Monique Pick, Alain Kerdraon, Dalmiro Maia, and Angelos Vourlidas

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• 549 x 443 color JPEG

If you would like to obtain a higher resolution version of this image, please contact Pat Smiley.

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• Read the Press Release
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Technical Data

Telescope	other
Date of Observation	1998-04-20
Type of Observation	Continuum Observations
Frequency	164 MHz
Technical Caption	Brightness of the CME is saturated in the low corona because the map has been clipped at a level of 0.04 SFU beam-1, corresponding to a brightness temperature of TB ~ 2.6 × 105 K.

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