[1] Solar wind protons detected within Magnetic Holes (MHs) and Magnetic Decreases (MDs) are found to be preferentially heated perpendicular toB 0 . The MHs/MDs are associated with the phase-steepened edges of nonlinear Alfvén waves. The proton anisotropies can lead to the proton cyclotron and mirror mode plasma instabilities. We examine the Ponderomotive Force (PF), a phenomenon due to wave pressure gradients, and show that for this plasma regime and for phase-steepened Alfvén waves, the PF proton acceleration/energization will primarily be orthogonal to B 0 . It is suggested that accelerated ions create the MHs/MDs by a diamagnetic effect.

Abstract. For the sets of magnetic clo•ds studied in this workwe have shown the existence of a relationship between their peak magnetic field strength and peak velocity values, with a clear tendency that, clouds which move at, higher speeds also possess higher core magnetic field strengths. This result suggests a possible intrinsic property of magnetic clouds and also implies a geophysical consequence. The relatively low field strengths at low velocities is pres•mably the cause of the lack of intense storms during low speed e. jecta. There is also an indication that, this type of behavior is peculiar for magnetic clouds, whereas other types of non cloud-driver gas events do not, seem to show a similar relationship, at least, for the data studied in this paper. We suggest that, a field/speed relationship for magnetic clouds, as that obtained in our present study, could be associated with the cloud release and acceleration mechanism a.t the sun.Since for magnetic clouds the total field tyically has a substantial southward component, B•, our results in,ply that the interplanetary dawn-dusk electric field, given by v x Bs (where v is the cloud's velocity), is enhanced by both factors. Therefore, the consequent magnetospheric energization (that is governed by this electric field) becomes more efficient for the occurrence of magnetic storms.

The derivative nonlinear Schrödinger (DNLS) equation is derived by an efficient means that employs Lagrangian variables. An expression for the stationary wave solutions of the DNLS that contains vanishing and nonvanishing and modulated and nonmodulated boundary conditions as subcases is then obtained. The solitary wave solutions for elliptically polarized quasiparallel Alfvén waves in the magnetohydrodynamic limit (nonvanishing, unmodulated boundary conditions) are obtained. These converge to the Korteweg–de Vries and the modified Korteweg–de Vries solitons obtained previously for oblique propagation, but are more general. It is shown there are no envelope solitary waves if the point at infinity is unstable to the modulational instability. The periodic solutions of the DNLS are charcterized.

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