Articles | Volume 22, issue 8
Ann. Geophys., 22, 3033–3037, 2004
https://doi.org/10.5194/angeo-22-3033-2004
Ann. Geophys., 22, 3033–3037, 2004
https://doi.org/10.5194/angeo-22-3033-2004

  07 Sep 2004

07 Sep 2004

The pressure tensor in tangential equilibria

F. Mottez F. Mottez
  • Centre d’études des Environnements Terrestre et Planétaires, CETP/IPSL/CNRS, Vélizy, France

Abstract. The tangential equilibria are characterized by a bulk plasma velocity and a magnetic field that are perpendicular to the gradient direction. Such equilibria can be spatially periodic (like waves), or they can separate two regions with asymptotic uniform conditions (like MHD tangential discontinuities). It is possible to compute the velocity moments of the particle distribution function. Even in very simple cases, the pressure tensor is not isotropic and not gyrotropic. The differences between a scalar pressure and the pressure tensor derived in the frame of the Maxwell-Vlasov theory are significant when the gradient scales are of the order of the Larmor radius; they concern mainly the ion pressure tensor.