Abstract
The paper derives the complete formulations of polytropic behaviour for plasmas described by kappa distributions. This is achieved by employing both positive and negative types of phase-space kappa distributions of a Hamiltonian for a nonzero potential energy, while the cases of positive and negative potential energies are analysed separately. Then, we develop the general polytropic-barometric formula that describes the profiles of density, temperature, and thermal pressure. Furthermore, it is shown how the kappa and polytropic indices can be derived from observational measurements of the temperature altitude gradient. As an example, we calculated the kappa κ ≈ 3.35 and polytropic γ ≈ 0.74 indices of the terrestrial atmosphere at ∼100 km, revealing the existence of heating processes that add thermal energy to atmospheric particles.
Original language | English (US) |
---|---|
Article number | e202000041 |
Journal | Contributions to Plasma Physics |
Volume | 60 |
Issue number | 9 |
DOIs | |
State | Published - Oct 1 2020 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
Keywords
- kappa distributions
- polytropic index
- space plasmas