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Multi-wavelength studies from optical to radio wavelengths

“…a region of low Alfven speed) generated a shock wave that became visible as type II emission. Type II bursts above expanding soft X-ray loops have been reported also by Klassen et al (1999;2003). The loop expansion speed in the later case was estimated to be around 700 km s −1 .…”

“…Loop-loop interactions were also suggested by Pohjolainen (2003) to be the mechanism for repeated radio flaring. In that study it was essential to be able to identify the separate soft X-ray and EUV loop structures, in relation with the radio and hard X-ray source locations.…”

“…In a recent study by Mandrini et al (2004) a small active region (the size of an X-ray bright point) was shown to undergo an eruption, resulting in an EUV dimming and cusp, and which was later observed as a small magnetic cloud in the interplanetary space. Several SEP studies have used white light, EUV, X-ray, and radio data to determine where the particles get accelerated (e.g., Torsti et al 2002;2003).…”

Magnetic Fields of Solar Active Regions

“…On the other hand, puzzling correlations of homologous CMEs and MMFs in NOAA 9236 were reported by Zhang & Wang (2002); repeated flares were observed in NOAA 8996, in which instead of EFRs only MMFs were clearly identified (Pohjolainen 2003). If the MMFs really have close correlation with flare/CME activity we may anticipate that MMFs are current-carrying or have non-potential magnetic nature.…”

“…Studies to extract as much information as possible from the time-sequence of vector magnetograms related to the occurrence of solar energetic events were made by Falconer, Moore, & Gary (2002, 2003, and Leka & Barnes (2003a,b). So far, the following perspectives are considered by the above and other authors: 1) distribution of magnetic flux density, 2) total flux and flux imbalance (see Shi & Wang, 1994) in ARs, 3) length and morphology of magnetic neutral line, 4) field inclination, 5) gradients of B, B h , B z , 6) vertical Current J z , 7) twist parameter -α, 8) helicity density -rate and pattern, 8) shear angles, 9) free magnetic energy .…”