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Session 19 - The Sun.
Oral session, Monday, June 08

[19.05] On the Interplanetary Magnetic Field

S. J. Goldstein Jr. (U. Virginia)

The presently accepted model (Parker, 1963) has magnetic flux lines rooted to the photosphere that follow an Archimedean spiral into interstellar space. The currents necessary to produce such a model would quickly merge into a small number of current loops that produce dipole fields. There is no known way of generating or replacing them. It is also difficult to understand how the flux lines produce zero divergence as the fourth Maxwell equation requires. I propose that there is a uniform magnetic field in interplanetary space, that determined by Rand and Kulkarni (1989, Ap.J. 343, 760) for the local spiral arm. It has a strength of .16 nT and its direction differs from that of the sun's pole by less than 23 deg. The curved paths followed by the exciting particles for type III solar bursts seen from the Ulysses spacecraft (Reiner et al., 1995, Sci. 270, 461) are the result of the Lorentz force acting on the net charge of the exciting particles. I calculate charge to mass ratios for the first three of their four observations, in terms of the proton charge to mass ratio. The results are 1/87, 1/81, and -1/43. Since current rings in space expand, the global current rings recently observed in the corona from the SOHO spacecraft, the heliospheric current sheets, and certain magnetized clouds all provide mechanisms for generating large scale magnetic fields. Perhaps these mechanisms also generate the magnetic field in the spiral arm. If so, the stars in the arm have correlated spin axes.

Program listing for Monday