PLASMA HEATING DURING A CORONAL MASS EJECTION OBSERVED BY THE SOLAR AND HELIOSPHERIC OBSERVATORY

Journal Article · Fri Jul 01 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/735/1/17· OSTI ID:21576557

Murphy, N A; Raymond, J C

We perform a time-dependent ionization analysis to constrain plasma heating requirements during a fast partial halo coronal mass ejection (CME) observed on 2000 June 28 by the Ultraviolet Coronagraph Spectrometer (UVCS) aboard the Solar and Heliospheric Observatory (SOHO). We use two methods to derive densities from the UVCS measurements, including a density sensitive O V line ratio at 1213.85 and 1218.35 A, and radiative pumping of the O VI {lambda}{lambda}1032, 1038 doublet by chromospheric emission lines. The most strongly constrained feature shows cumulative plasma heating comparable to or greater than the kinetic energy, while features observed earlier during the event show plasma heating of order or less than the kinetic energy. SOHO Michelson Doppler Imager observations are used to estimate the active region magnetic energy. We consider candidate plasma heating mechanisms and provide constraints when possible. Because this CME was associated with a relatively weak flare, the contribution from flare energy (e.g., through thermal conduction or energetic particles) is probably small; however, the flare may have been partially behind the limb. Wave heating by photospheric motions requires heating rates to be significantly larger than those previously inferred for coronal holes, but the eruption itself could drive waves that heat the plasma. Heating by small-scale reconnection in the flux rope or by the CME current sheet is not significantly constrained. UVCS line widths suggest that turbulence must be replenished continually and dissipated on timescales shorter than the propagation time in order to be an intermediate step in CME heating.

• OSTI ID: 21576557
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 735; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ATMOSPHERES
DENSITY
EMISSION
HEATING
IONIZATION
MAGNETIC RECONNECTION
MASS
PHYSICAL PROPERTIES
PLASMA HEATING
SOLAR ATMOSPHERE
SOLAR CORONA
STELLAR ATMOSPHERES
STELLAR CORONAE
TIME DEPENDENCE