Interplanetary stream magnetism - Kinematic effects

The particle density, and the magnetic field intensity and direction, are calculated for volume elements of the solar wind as a function of the initial magnetic field direction, Phi$sub 0$, and the initial speed gradient, (deltaV/ deltaR)$sub 0$. It is assumed that the velocity is constant and radial. These assumptions are approximately valid between approx.0.1 and 1.0 AU for many streams. Time profiles of n, B, and V are calculated for corotating streams, neglecting effects of pressure gradients. The compression and rarefaction of B depend sensitively on Phi$sub 0$. By averaging over a typical stream, it is found that approx.r$sup -2$, whereas does not vary in a simple way, consistent with deep space observations. Changes of field direction may be very large, depending on the initial angle; but when the initial angle at 0.1 Au is such that the base of the field line corotates with the Sun, the spiral angle is the preferred direction at 1 AU. The theory is also applicable to nonstationary flows. (AIP)