Uncertainties in the heliosheath ion temperatures

Abstract

The Voyager plasma observations show that the physics of the heliosheath is rather complex, and especially that the temperature derived from observation differs from expectations. To explain this fact the temperature in the heliosheath should be based on $\kappa$ distributions instead of Maxwellians because the former allows for much higher temperature. Here we show an easy way to calculate the $\kappa$ temperatures when those estimated from the data are given as Maxwellian temperatures. We use the moments of the Maxwellian and $\kappa$ distributions to estimate the $\kappa$ temperature. Moreover, we show that the pressure (temperature) given by a truncated $\kappa$ distribution is similar to that given by a Maxwellian and only starts to increase for higher truncation velocities. We deduce a simple formula to convert the Maxwellian to $\kappa$ pressure or temperature. We apply this result to the Voyager-2 observations in the heliosheath.

9 pages 7 Figures

References in corpus (5)

• The effects of a kappa-distribution in the heliosheath on the global heliosphere and ENA flux at 1 AU
• On the interpretation and applicability of $\kappa$-distributions
• Dual Maxwellian-Kappa modelling of the solar wind electrons: new clues on the temperature of Kappa populations
• Misestimation of temperature when applying Maxwellian distributions to space plasmas described by kappa distributions
• Pickup Ion Effect of the Solar Wind Interaction with the Local Interstellar Medium

Cited by in corpus (2)

• On the entropy of plasmas described with regularized $\kappa$-distributions
• Concerning pressure and entropy of shock-accelerated heliosheath electrons