Development of the solar flare plasma density investigation method based on the 2.2 MeV gamma-line time profile analysis

Solar Cosmic Rays

“…These include (e.g., Share and Murphy 2000): (1) enhancements in the concentration of low FIP elements where accelerated particles interact; (2) a new line ratio for deriving the spectra of accelerated particles at 10 MeV; (3) energies in accelerated ions that exceed those in electrons for some flares; (4) a highly variable ion to electron ratio during flares; (5) concentration of 3 He in flareaccelerated particles enhanced by a factor of !1,000 over its possible photospheric value; (6) an accelerated α/p ratio >0.1 in several flares and evidence for high ambient 4 He in some flares; (7) measurement of the positronium fraction and a temperature-broadened 511 keV line width; (8) new information on the directionality of electrons, protons, and heavy ions and/or on the homogeneity of the interaction region; and (9) the spectrum of broadened gamma-ray lines emitted by accelerated heavy ions that indicates Fe enhancements consistent with those observed in solar energetic particles. In addition to these important findings, Kuzhevskij et al (1998Kuzhevskij et al ( , 2005a have developed a new method for investigation of the solar flare plasma density based on the analysis of the 2.223 MeV gammaline time profiles (for some details see Chap. 12).…”

Solar Plasma Density and Spectrum of Accelerated Particles Derived From the 2.223-Mev Line of a Solar Flare

“…For the first time, the latter assumption seems to be empirically substantiated and applied by Prince et al (1983). Theoretical treatment of this assumption has been accomplished by Kuzhevskij and Kogan-Laskina (1990).…”

“…As a basic density model (BDM) (m = 1) we have used a combination of the standard astrophysical model HSRA (Harvard-Smithsonian Reference Atmosphere) for the lower chromosphere and quiet photosphere (Gingerich et al, 1971) with the model for the convection zone (Spruit, 1974). To determine possible deviations of the model, which may be possible for a given observable flare, from the BDM, we have also composed four additional models (m = 2, 3, 4, 5) representing smaller and larger densities at photospheric and adjoining levels as compared with the standard model (m = 1) of the quiet Sun (e.g., Kuzhevskij, Kuzhetsov, and Troitskaia, 1998).…”

“…In particular, of great importance are the data on the events of 23 July 2002, October to November 2003, 20 January 2005, obtained by RHESSI, CORONAS-F, and INTEGRAL. At the same time, it seems to be reasonable to include in the SINP calculation code introduced about ten years ago (Kuzhevskij and Troitskaia, 1995;Kuzhevskij, Kuzhetsov, and Troitskaia, 1998) some new basic density models of the solar atmosphere developed since the 1970s (e.g., Avrett, 1981;Vernazza, Avrett, and Loeser, 1981).…”

“…More recently, Kuzhevskij, Kuzhetsov, and Troitskaia (1998), , Troitskaia (2001, 2002), Gan et al (2003), Troitskaia et al (2003) and Kuzhevskij, Miroshnichenko, and Troitskaia (2005) have developed a new independent approach (SINP code) to determine, by the time profile data of the 2.223-MeV line, the most probable profile of plasma density in the solar photosphere and adjoining levels during the period of a flare. The idea of such an approach was first suggested in 1986 (see Kuzhevskij and Troitskaia, 1995).…”