Authors: L.Simeonov, M.Hilchenbach, B.Klecker, R.Kallenbach, K.Bamert
and D.McMullin.
Reference: Proc. of the 9th Conf. on contemporary problems of the
solar-terrestrial influences. Sofia, 21-21.Nov. 2002, p.85-88.
Abstract:
The measurements with the STOF/STOF and HSTOF instrument of
the CELIAS/SOHO sensor allow the determination of the energy, mass and
ionic charge of suprathermal energetic particles of gradual and/or
inpulsive solar particle events. The dynamics of an energetic solar
particle event could be described by its time-profile, including the
rising phase to the highest intensity or the "time to maximum", the
maximum itself and the decaying phase of the event. The "time to
maximum" in a solar event is found to be a function of the charge- to
-mass ratio of the observed elements. In the case of Fe the onset phase
could differ for single energetic events, being a function not only of
the velocity of the ion, but also of its state of ionization, i.e on the
extent of stripping. The question is whether some quantitative
dependence between the "time to maximum" and the charge/mass for
individual elements (for example, H, He, O, Fe) could be derived from
the STOF/HSTOF data, thus providing additional evidence to the
problematic of solar energetic events, especially concerning the
diffusive propagation of particles. In the paper this problematic is
discussed, featuring the gradual solar particle event, detected on 30
June 2000 or 181DoY2000. As an example, plots from HSTOF and ULEIS on
ACE, concerning the time profiles of O and Fe, and especially the
different ?time to maximum? of the elements are presented. Reference
X-ray plot from GOES and a picture from LASCO/SOHO is used for
additional identification of the chosen solar event.