## Abstract

[1] The acceleration of current carriers in an Alfven wave current system is considered. The model incorporates a dipole magnetic field geometry, and we present an analytical solution of the two-fluid equations by successive approximations. The leading solution corresponds to the familiar single-fluid toroidal oscillations. The next order describes the nonlinear dynamics of electrons responsible for carrying a few muAm(-2) field aligned current into the ionosphere. The solution shows how most of the electron acceleration in the magnetosphere occurs within 1 R-E of the ionosphere, and that a parallel electric field of the order of 1 mV m(-1) is responsible for energising the electrons to 1 keV. The limitations of the electron fluid approximation are considered, and a qualitative solution including electron beams and a modified E-parallel to is developed in accord with observations. We find that the electron acceleration can be nonlinear, (nu(eparallel to)del(parallel to))nu(eparallel to) > omeganu(eparallel to), as a result of our nonuniform equilibrium field geometry even when nu(eparallel to) is less than the Alfven speed. Our calculation also elucidates the processes through which E-parallel to is generated and supported.

Original language | English |
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Article number | 1120 |

Number of pages | 15 |

Journal | Journal of Geophysical Research |

Volume | 107 |

Issue number | A7 |

DOIs | |

Publication status | Published - Jul 2002 |

## Keywords

- LINE RESONANCES
- DIPOLAR MAGNETOSPHERE
- ELECTROSTATIC SHOCKS
- PONDEROMOTIVE FORCE
- GEOMAGNETIC-FIELD
- PLASMA
- LAYERS
- ARCS
- ZONE