Eur. Phys. J. B (2014) 87: 91
https://doi.org/10.1140/epjb/e2014-50136-y

Regular Article

Velocity filtration and temperature inversion in a system with long-range interactions

¹ Dipartimento di Fisica e Astronomia and CSDC, Università di Firenze, and INFN, Sezione di Firenze, via G. Sansone 1, 50019 Sesto Fiorentino, Italy
² INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
³ Laboratoire de Physique Théorique et Modèles Statistiques (CNRS UMR 8626), Université Paris-Sud, 91400 Orsay, France

^a e-mail: lapo.casetti@unifi.it

Received: 10 December 2013
Received in final form: 28 February 2014
Published online: 14 April 2014

Abstract

Temperature inversion due to velocity filtration, a mechanism originally proposed to explain the heating of the solar corona, is demonstrated to occur also in a simple paradigmatic model with long-range interactions, the Hamiltonian mean-field model. Using molecular dynamics simulations, we show that when the system settles into an inhomogeneous quasi-stationary state in which the velocity distribution has suprathermal tails, the temperature and density profiles are anticorrelated: denser parts of the system are colder than dilute ones. We argue that this may be a generic property of long-range interacting systems.