A new class of empty-space metrics is obtained, one member of this class being a natural generalization of the Schwarzschild metric. This latter metric contains one arbitrary parameter in addition to the mass. The entire class is the set of metrics which are algebraically specialized (contain multiple-principle null vectors) such that the propagation vector is not proportional to a gradient. These metrics belong to the Petrov class type I degenerate.

The asymptotic behavior of the Weyl tensor and metric tensor is investigated for probably all asymptotically flat solutions of the empty space Einstein field equations. The systematic investigation utilizes a set of first order differential equations which are equivalent to the empty space Einstein equations. These are solved asymptotically, subject to a condition imposed on a tetrad component of the Riemann tensor ψ0 which ensures the approach to flatness at spatial infinity of the space-time. If ψ0 is assumed to be an analytic function of a suitably defined radial coordinate, uniqueness of the solutions can be proved. However, this paper makes considerable progress toward establishing a rigorous proof of uniqueness in the nonanalytic case. A brief discussion of the remaining coordinate freedom, with certain topological aspects, is also included.

Mariner II plasma and magnetic-field data are examined for explicit examples of low-frequency hydromagnetic waves. From the magnetic-field data, several sinusoidal waveforms are isolated. One of these clearly satisfies the hydromagnetic equations relating the magnetic-field variation to the ion-velocity perturbation for an Alfvén wave. This result is consistent with Barnes' theoretical prediction that only the Alfvén mode is not strongly damped in a plasma of moderate or high β.

A new coordinate system, intrinsically attached to an arbitrary timelike world line, is investigated in flat-space time. The Maxwell field tensor associated with the field of an arbitrarily moving charged particle assumes a particularly simple form in this, its intrinsic coordinate system. This reference frame is expected to be useful in General Relativity, in asymptotic studies of radiation, and equations of motion.

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The shock system observed in the solar wind by Pioneer 9 and Ogo 5 on February 2, 1969, consisted of the following major discontinuities: a forward slow shock, a forward fast shock, a tangential discontinuity at which the density dropped sharply and the flow direction changed, a tangential discontinuity at which the magnetic field strength jumped to an unusually high value, two closely spaced tangential discontinuities that bracketed a region of even greater field strength and that fronted a region of very cool, very dense, helium‐enriched plasma, a reverse fast shock of low Mach number, and a second reverse fast shock of very low Mach number. The event had aspects of both corotating and flare‐induced shock systems; it is suggested that the source of the disturbances was a flare occurring at or near an M region. The Ogo 5 search coil magnetometer detected a high level of turbulence throughout the event; a local enhancement of this turbulence at the front of the helium enrichment is believed to have been caused by a magnetic drift wave instability. Data are also presented for two other shock pair systems, both of which had density and flow direction profiles similar to those observed on February 2, 1969.

An exact solution to a two‐dimensional magnetosphere with tail and neutral sheet using the Chapman‐Ferraro approximation has been found by mapping in the potential plane. The magnetic flux in the tail is an arbitrary parameter of the problem. Boundary and neutral sheet configurations are presented for several values of tail flux. It is found that the position of the neutral sheet and its return current on the outer boundary is very sensitive to the amount of magnetic flux in the tail. The relationship with the three‐dimensional case is discussed, and it is concluded that the neutral sheet probably moves in and out by several earth radii. This suggests the following large‐scale convective flow pattern for the magnetosphere. Between magnetospheric substorms, field lines are carried into the tail, which causes an increase in tail flux, an inward motion of the neutral sheet, and a two‐celled ionospheric current system. The magnetospheric substorm then chops off the inner edge of the neutral sheet, returning the system to its initial topology.

In a magnetosphere with a magnetic tail and a perfect neutral sheet, the steady‐state field line configuration is found to depend on two variables: the magnetic flux in the tail and the solar wind momentum flux. Thus, changes in solar wind momentum flux, or transport of magnetic field lines into and from the tail cause a large‐scale magnetospheric flow toward the new equilibrium configuration. The solutions to the two‐dimensional case are used to study the flows and indicate the following: (1) Changes of the momentum flux of the solar wind are important in producing convective flow, only if they are an order of magnitude in a short time. (2) The large‐scale convective flow is usually determined to first order by the rate at which field lines are being carried into the tail and is probably not dependent on occurrences at the neutral sheet. (3) Reconnection and collapse of tail field lines to a dipolar‐like configuration could produce significant magnetosphere‐wide flow only if it was burst‐like in occurrence. The magnetospheric response to forces that produce flows depends on the relative size of three time constants: The time constant of the driving force, the time to set up a stressed magnetosphere, and the time to relax it by motion of field line feet through the conducting ionosphere.