Micro-events in the active and quiet solar corona
arXiv:astro-ph/0308323 · doi:10.1016/S0273-1177(03)00306-5
Abstract
The content of hot material in the corona is not constant. Soft X-ray and high-temperature EUV line observations show that new material, apparently heated and evaporated from the chromosphere, is frequently injected into the corona both in active and quiet regions. Active regions are found to exhibit transient brightenings, termed here microflares, due to such enhancements in emission measure. They appear at a rate of up to 10 per hour in RHESSI observations of 3--15 keV X-rays, occurring even during the periods of lowest solar activity so far in the mission. The RHESSI observations combined with measurements at other wavelengths yield estimates of the energy input into the corona. These observations suggest that the models for coronal heating must be complemented with respect to continuous replenishing the lower corona by chromospheric material heated to coronal temperatures. The observed micro-events are secondary phenomena and do not represent the primary energy release, nor its total amount. Nevertheless, they are an interesting source of information on the heating process(es) of the corona. The micro-events are compared to events in quiet regions, termed here nanoflares, which seem to be a different population, well separated in temperature and emission measure from microflares.
COSPAR meeting Houston 2002, PASP proceedings, in press
References in corpus (4)
Cited by in corpus (6)
- RHESSI Microflare Statistics II. X-ray Imaging, Spectroscopy & Energy Distributions
- Solar Corona Heating by the Axion Quark Nugget Dark Matter
- Axion Quark Nuggets. Dark Matter and Matter-Antimatter asymmetry: theory, observations and future experiments
- Solar Extreme UV radiation and quark nugget dark matter model
- Radio impulsive events in quiet solar corona and Axion Quark Nugget Dark Matter
- Neutron Stars as the Dark Matter detectors