Mass and energy of erupting solar plasma observed with the X-Ray Telescope on Hinode

TL;DR

This study analyzes seven eruptive solar plasmas observed with Hinode/XRT, determining their temperatures, masses, and energies, and discusses implications for plasma heating during eruptions.

Contribution

First detailed analysis of eruptive plasma temperatures, masses, and energies using Hinode/XRT data, providing new insights into plasma properties and heating during solar eruptions.

Findings

Temperatures range from 1.6 to 10 MK.

Mass estimates are lower than total CME masses.

Thermal conduction timescales suggest additional heating is needed.

Abstract

We investigate seven eruptive plasma observations by Hinode/XRT. Their corresponding EUV and/or white light CME features are visible in some events. Five events are observed in several passbands in X-rays, which allows the determination of the eruptive plasma temperature using a filter ratio method. We find that the isothermal temperatures vary from 1.6 to 10 MK. These temperatures are an average weighted toward higher temperature plasma. We determine the mass constraints of eruptive plasmas by assuming simplified geometrical structures of the plasma with isothermal plasma temperatures. This method provides an upper limit to the masses of the observed eruptive plasmas in X-ray passbands since any clumping causes the overestimation of the mass. For the other two events, we assume the temperatures are at the maximum temperature of the XRT temperature response function, which gives a lower limit of the masses. We find that the masses in XRT, ~3x10 13 - 5x10 14 g, are smaller in their upper limit than total masses obtained by LASCO, ~1x10 15 g. In addition, we estimate the radiative loss, thermal conduction, thermal, and kinetic energies of the eruptive plasma in X-rays. For four events, we find that the thermal conduction time scales are much shorter than the duration of eruption. This result implies that additional heating during the eruption may be required to explain the plasma observations in X-rays for the four events.