solar flare events of high importance were utilised to study solar latitudinal frequency distribution of the solar flares in northern and southern hemisphere for the solar cycle 22 to recent solar cycle 23. a statistical analysis was performed to obtain their relationship with sudden storm commencement (sscs) and forbush decrease events (fd) of cosmic ray intensity. an 11-year cyclic variation ...

Solar flare events of high importance were utilised to study solar latitudinal frequency distribution of the solar flares in northern and southern hemisphere for the solar cycle 22 to recent solar cycle 23. A statistical analysis was performed to obtain their relationship with sudden storm commencement (SSCs) and Forbush decrease events (Fd) of cosmic ray intensity. An 11-year cyclic variation ...

We present an overview of solar flares and associated phenomena, drawing upon a wide range of observational data primarily from the RHESSI era. Following an introductory discussion and overview of the status of observational capabilities, the article is split into topical sections which deal with different areas of flare phenomena (footpoints and ribbons, coronal sources, relationship to corona...

Observations of the green and red-doublet emission lines have previously been realized for several comets. We present here a chemistry-emission coupled model to study the production and loss mechanisms of the O(1S) and O(1D) states, which are responsible for the emission lines of interest for comet 67P/Churyumov-Gerasimenko. The recent discovery of O2 in significant abundance relative to water ...

The effects of solar flares on the propagation of subionospheric VLF signals from NWC and NLK transmitter stations monitored at a low-latitude station, Suva (18.2°S, 178.4°E), Fiji, between December 2006 and December 2010 (an unprecedented solar minimum of solar cycles 23 and 24) and between January 2012 and December 2013 (moderate solar activity at the peak of solar cycle 24) have been analyze...

In this study we compile for the first time comprehensive data sets of solar and stellar flare parameters, including flare peak temperatures Tp, flare peak volume emission measures EMp, and flare durations τf from both solar and stellar data, as well as flare length scales L from solar data. Key results are that both the solar and stellar data are consistent with a common scaling law of EMp ∝ T...

Flare occurrence is statistically associated with changes in several characteristics of the line-of-sight magnetic field in solar active regions (AR). We calculated magnetic measures throughout the disk passage of 1,075 ARs spanning solar cycle 23 in an attempt to find a statistical relationship between the solar magnetic field and solar flares. This expansive study of over 71,000 magnetograms ...

Aims. The purpose of this work is to search the Yangbajing neutron monitor data obtained between 1998 October and 2000 June for solar neutrons associated with solar flares. Methods. Using the onset times of 166 BATSE-detected flares with the GOES peak flux (1 – 8 Å) higher than 1.0 × 10−5 Wm−2, we prepare for each flare a light curve of the Yangbajing neutron monitor, spanning ± 1.5 hours from ...

We have performed the first polarimetry of solar flare emission at γ-ray energies (0.2–1MeV). These observations were performed with the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) for two large flares: the GOES X4.8-class solar flare of 2002 July 23, and the X17-class flare of 2003 October 28. We have marginal polarization detections in both flares, at levels of 21 ± 9% and -...

By introducing a hitherto ignored Li producing process, due to accelerated He reactions with He, we show that accelerated particle interactions in solar flares produce much more Li than Li. By normalizing our calculations to gamma-ray data we demonstrate that the Li produced in solar flares, combined with photospheric Li, can account for the recently determined solar wind lithium isotopic ratio...