Abstract
We consider the Alfvén-Arrhenius fall-down mechanism and describe an approximate model for the infall, capture and distribution of dust particles on a given magnetic field line and their possible neutralization at the ‘2’/3 points, the points at which the field aligned compnents of the gravitational and centrifugal forces are equal and opposite. We find that a small fraction (<10%) of an incoming particle distribution will actually contribute to the above ‘2’/3 fall-down process. We also show that if at the 2/3 points, the ratio of dust to plasma density is
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(r gμ=radius of a grain in microns,T=plasma temperature in eV), then the dust particles will lose their charge, decouple from the field line and follow Keplerian orbits in accordance with the Alfvén-Arrhenius mechanism.
We then determine the limits on the plasma parameters in order that rotation of a quasi-neutral plasma in thermal equilibrium be possible in the gravitational and dipole field of a rotating central body. The constraints imposed by the above conditions are rather weak, and the plasma parameters can have a wide range of values. For a plasma corotating with an angular velocity Ω∼10−4s−1, we show that the plasma temperature and density must satisfy
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Paper dedicated to Professor Hannes Alfvén on the occasion of his 80th birthday, 30 May 1988.
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Azar, M., Thompson, W.B. The cosmogonic shadow effect. Astrophys Space Sci 144, 373–406 (1988). https://doi.org/10.1007/BF00793194
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DOI: https://doi.org/10.1007/BF00793194