ISSN:
1573-093X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Near solar maximum, hard X-ray microflares with peak 20 keV fluxes of ≳10−2 (cm2 s keV)−1, more than ten times smaller than for typical flares and subflares, can occur at the rate of about once every five minutes. We report here on a search for hard X-ray microflares made on a long duration balloon flight in February 1987 near solar minimum, at a time when no active regions were on the Sun. No microflares were observed over a total observing time of 16.5 hours spread over three days, implying a statistical upper limit to their rate of occurrence about a factor often lower than observed near solar maximum. Thus hard X-ray microflaring appears to be an active region phenomenon, and apparently not associated with flaring of soft X-ray bright points.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00146698
