Nonlinear time evolution of thermal structures

Abstract

The nonlinear stability and time evolution of thermal structures constituted by optically thin plasmas are analyzed. The structure has been assumed to be heated at a rate ∼Tm, cooled by the standard cooling function for plasmas with solar abundances and with an anisotropic thermal conduction coefficient. Second-order analytical results are obtained for the thermal equilibrium solutions. For nonhomogeneous solutions and strong disturbances, a numerical analysis is carried out. The angle between the temperature gradient and the magnetic field is a crucial parameter in determining the stability of structures close to the marginal state. A central overheating may occur for large enough amplitudes of the initial disturbance imposed on stable steady-state thermal structures. Implications of the above results in the formation of cool structures in the solar atmosphere and in the interstellar medium are outlined.

Electromagnetic Thermal Instability With Momentum and Energy Exchange Between Electrons and Ions in Galaxy Clusters

“…This instability was studied for rotating (e.g., Field 1965;Nipoti 2010), expanding (e.g., Field 1965;Gomez-Pelaez & Moreno-Insertis 2002), and dynamical systems with steady or time-dependent flows and nonstationary background parameters (e.g., Mathews & Bregman 1978;Balbus 1986;Balbus & Soker 1989;Burkert & Lin 2000). The nonlinear stage of the thermal instability resulting in formation of nonlinear structures (localized clouds) in the ISM and solar prominences was investigated in (e.g., Trevisan & Ibáñez 2000;Sánchez-Salcedo et al 2002;Yatou & Toh 2009) and (Mason & Bessey 1983;Karpen et al 1989;Trevisan & Ibáñez 2000), respectively.…”

Influence of energy exchange of electrons and ions on the long-wavelength thermal instability in magnetized astrophysical objects

“…The non‐linear stage of thermal instability resulting in the formation of non‐linear cool structures was investigated in the ISM (e.g. Trevisan & Ibáñez 2000; Sánchez‐Salcedo et al 2002; Yatou & Toh 2009) and solar corona (Mason & Bessey 1983; Karpen et al 1989; Trevisan & Ibáñez 2000).…”

“…In galaxy clusters, this instability, including the presence of the magnetic field, was studied in (e.g., Field 1965;Loewenstein 1990;Balbus 1991;Bogdanović et al 2009;Parrish et al 2009;Sharma et al 2010). The nonlinear stage of thermal instability resulting in formation of nonlinear cool structures was investigated in the ISM (e.g., Trevisan & Ibáñez 2000;Sánchez-Salcedo et al 2002;Yatou & Toh 2009) and solar corona (Mason & Bessey 1983;Karpen et al 1989;Trevisan & Ibáñez 2000).…”