Misestimation of temperature when applying Maxwellian distributions to space plasmas described by kappa distributions

Misestimation of temperature when applying Maxwellian distributions to space plasmas described by kappa distributions

This paper presents the misestimation of temperature when observations from a kappa distributed plasma are analyzed as a Maxwellian. One common method to calculate the space plasma parameters is by fitting the observed distributions using known analytical forms. More often, the distribution function is included in a forward model of the instrument’s response, which is used to reproduce the obse...

Firehose instability in space plasmas with bi-kappa distributions

Context. The existence of suprathermal charged particle populations in space plasma is frequently confirmed by interplanetary missions. In general, the velocity distribution functions are anisotropic, field aligned (gyrotropic) with two temperatures, parallel (T‖) and perpendicular (T⊥) to the ambient magnetic field B0. Aims. Here, the dispersion properties of the firehose instability, which re...

"Lagrangian Temperature": Derivation and Physical Meaning for Systems Described by Kappa Distributions

The paper studies the “Lagrangian temperature” defined through the entropy maximization in the canonical ensemble, which is the negative inverse Lagrangian multiplier corresponding to the constraint of internal energy. The Lagrangian temperature is derived for systems out of thermal equilibrium described by kappa distributions such as space plasmas. The physical meaning of temperature is manife...

Nongyrotropic particle distributions in space plasmas

In nonstationary, strong inhomogeneous or open plasmas particle orbits are rather complicated. If the nonstationary time scale is smaller than the gyration period, if the inhomogeneity scale is smaller than the gyration radius, i.e. at magnetic plasma boundaries, or if the plasma has sources and sinks in phase space, then nongyrotropic distribution functions occur. The stability of such plasma ...

Ion-acoustic supersolitons in plasmas with two-temperature electrons: Boltzmann and kappa distributions