ALBERT

Notes: Abstract Theoretical models of magnetic reconnection are reviewed with a critical view of their suitability for astrophysical plasmas, with a focus on those sampled plasmas near the magnetopause. Frequently the approximations are more those of convenience than physically justified. It is concluded that magnetic reconnection cannot be qualitatively or quantitatively addressed with any one fluid MHD picture unless the Hall, ambipolar and inertial emfs are included in the Generalized Ohm's Law. The observed size of electron pressure anisotropies ensures that the thawing of magnetic flux is almost always determined by the often neglected ambipolar term of the Generalized Ohm's Law. Thus resistive MHD or even resistive Hall MHD cannot possibly give a correct structural picture of the reconnection current carrying layer at the magnetopause. In the magnetotail the ion inertial "resistivity" is much larger than coulomb resistivity with a similar structural form as the coulomb emf. However, until recently the ambipolar contributions there have not been considered. This change in viewpoint of the controlling factors for thawing of magnetic flux parallels the recent evolution of understanding of collisionless shocks, where initially stochastic wave-resistivities were thought to substitute for the coulomb dissipation of high density shock waves. Now these shocks are known to be controlled by coherent agents that can modify emf's such as the ambipolar electric field, the Hall contributions of the gyrating ions, and the electric electron drift in the shock layer to support the current without thawing flux and without any requirement of ohmic dissipation per se. The observational tests that reconnection is a viable process for plasma entry in the magnetosphere are briefly reviewed. Sites where these conservation laws are said to be approximately fulfilled are discussed with an eye toward systematic experimental issues of these tests. That magnetic shear poorly indexes "good" Walén testing layers may be an indication that the resistive dissipation is either not uniformly important across the data set or resistive emf's are not the appropriate agent for the thawing of flux. The ambipolar scale length clearly exceeds the resistive or electron skin depth regime with layers that pass the "good" Walén test layers which have β 〈 5; this may indicate the importance of the ambipolar violations to the frozen field description.

Notes: Abstract The Solar Wind Experiment (SWE) on the WIND spacecraft is a comprehensive, integrated set of sensors which is designed to investigate outstanding problems in solar wind physics. It consists of two Faraday cup (FC) sensors; a vector electron and ion spectrometer (VEIS); a strahl sensor, which is especially configured to study the electron ‘strahl’ close to the magnetic field direction; and an on-board calibration system. The energy/charge range of the Faraday cups is 150 V to 8 kV, and that of the VEIS is 7 V to 24.8 kV. The time resolution depends on the operational mode used, but can be of the order of a few seconds for 3-D measurements. ‘Key parameters’ which broadly characterize the solar wind positive ion velocity distribution function will be made available rapidly from the GGS Central Data Handling Facility.

Notes: Abstract A survey, using results from the first 25 orbits of ISEE-1, has been made of some aspects of electrons in the dawn magnetosheath. There are indications that the flow of plasma is not uniformly turbulent over this region. The electron heat flux is observed to be directed away from the shock and to have an average value of about twice the interplanetary heat flux. Many magnetopause crossings were observed and usually resemble abrupt transitions from one well-defined plasma state to another. The ejection of plasma from flux tubes converted up against the magnetopause is observed for about half the time, and its thickness and dependence on the solar wind mach number agree with theoretical predictions. A full traversal of the whole forward hemisphere of the magnetosheath is required to fully confirm these deductions.