Go to previous page Go up Go to next page

2.5 The inhomogeneous case

Equations (16View Equation) refer to the standard homogeneous and incompressible MHD. Of course, the solar wind is inhomogeneous and compressible and the energy transfer equations can be as complicated as we want by modeling all possible physical effects like, for example, the wind expansion or the inhomogeneous large-scale magnetic field. A set of equations for the cross-correlation functions of both Elsässer fluctuations have been developed independently by Marsch and Tu (1989Jump To The Next Citation Point), Zhou and Matthaeus (1990), Oughton and Matthaeus (1992), and Tu and Marsch (1990aJump To The Next Citation Point), following Marsch and Mangeney (1987Jump To The Next Citation Point) (see review by Tu and Marsch, 1996Jump To The Next Citation Point), and are based on some rather strong assumptions: i) a two-scale separation, and ii) small-scale fluctuations are represented as a kind of stochastic process (Tu and Marsch, 1996Jump To The Next Citation Point). These equations look quite complicated, and just a comparison based on order-of-magnitude estimates can be made between them and solar wind observations (Tu and Marsch, 1996).
  Go to previous page Go up Go to next page