Authors: M.R. Aellig, P. Bochsler, H. Grünwaldt, S. Hefti, P. Wurz, M. Hilchenbach, D. Hovestadt F.M. Ipavich, and F. Gliem
Reference: Phys. Chem. Earth (C), Vol. 24, No. 4, pp 407-414, 1999.
The CELIAS/CTOF\,(Charge Time Of Flight) mass spectrometer on board the
measures the ionic and elemental composition of minor ions in the
solar wind. From density ratios of adjacent charge states of minor
ions we derive, consistent with previous measurements of the same
type, mean freeze-in temperatures in the slow solar wind in the range
between about 1.1 x 106 K and 1.6 x 106 K depending
upon the charge states and elements considered.
These values are obtained assuming a Maxwellian distribution of the
electrons in the inner corona. We assess the influence of suprathermal
electrons in the corona upon the density ratios and,
subsequently, on the temperature estimates that are drawn from minor
ion charge spectra.
It was found that only limited amounts of suprathermal
electrons are compatible with the charge state observations in the
slow solar wind.