fl198.yoshimori09 Posted: 01-Mar-95 Updated: 17-Jul-95, 08-Apr-96 Events specified: Flare of 15-Nov-91 22:35 UT
Collaboration: M.Yoshimori (yosimori@rikkyo.ac.jp), K.Morimoto, K.Suga, T.Matsuda and K.Kawabata
Yohkoh observed both Li-Be gamma-ray lines and hard X-ray images from a disk flare on 15 November 1991. The Li-Be lines resulting from He-He reactions were redshifted by 7 %, suggesting that the angular distribution of accelerated He nuclei was peaked in a downward direction. The hard X-ray images showed simultaneous brightening double sources in >30 keV, suggesting that the accelerated-electrons precipitated to two footpoints of a flaring loop and produced hard X-rays by bremsstrahlung (Sakao, 1994). These two observations provide evidence for the downward beaming of the accelerated- electrons and ions.
Required observations: Hard X-ray spectrum and hard X-ray images of the 1991 November15 flare.
Update 08-Apr-96
We have reached the goal of the proposal fl198 updated 17-July-95.
Title: "Downward Beaming of Ions and Electrons in the 1991 Novbember 15 Flares "
Authors: M.Yoshimori, K.Morimoto, K.Suga, T.Matsuda and K.Kawabata
This paper was published in Proc. of 24th International Cosmic Ray Conference vol.3 (1995) 98.
Abstract
Yohkoh observed both Li-Be gamma-ray lines and hard X-ray images from a disk flare on 15 November 1991. The Li-Be lines resulting from He-He reactions showed redshift of 7 %, indicating the possibility that the angular distribution of of the accelerated He nuclei was peaked in the downward direction. The hard X-ray image observed in 33 - 93 keV showed simultaneous brightening double sources, indicating the possibility that accelerated electrons precipitated to both footpoints of the flaring loop. These Li-Be line and hard X-ray observations suggest the downward beaming of the accelerated ions and electrons.
Update: 17-Jul-95
Yohkoh observed both Li-Be gamma-ray lines and hard X-ray images from a disk-centered flare on 15 November 1991. The Li and Be lines resulting from He-He reactions showed redshift of 7 %, suggesting the possibility that the angular distribution of the accelrated He nuclei was peaked in the downward direction. The hard X-ray images in 33 - 56 and 56 - 93 keV bands showed simultaneous brightening double sources, indicationg that the accelerated electrons precipitated to both foof the flaring loop and produced hard X-rays through bremsstrahl(Rome, S ung. These observations give suggestion of the downward beaming of the accelerated ions and electrons.
This paper was presented in the IAU Colloquium #153 (Makuhari, May 22 - 26, 1995) and is presented in the 24th International Cosmic Ray Conference (Rome, Aug.27 - Sept.8, 1995).