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We develop a self-consistent, three-dimensional method for the calculation of the steady-state acceleration of nonneutral plasma at the surface of a rotating, magnetized, isolated neutron star. When the effects of surface work functions are negligible, there is a unique monotonic electrostatic potential and associated current profile. We obtain explicit solutions in the monopole and polar-cap geometries. In the latter, we neglect field-line curvature and consider only the aligned rotator. The maximum asymptotic particle energy in the polar-cap case, achieved along the central field line, is found to be E/sub max/=2.8 x 10/sup 9/ eV x (P/1 s)/sup -1/(B/10/sup 12/ gauss)/sup 1/2/(R/sub asterisk6/ cm)/sup 1/2/(Zm/m/sub e/)/sup 1/2/. This result is in good accord with previous estimates made by Michel. The total luminosity of the pulsar in the form of each charged-particle beam from a polar cap is L/sub cap/=4 x 10/sup 27/(P/1 s)/sup -3/(B/10/sup 12/ gauss)/sup 3/2/ (R/sub asterisk6/ cm)/sup 9/2/(m/Zm/sub e/)/sup 1/2/ ergs s/sup -1/. This luminosity is sufficient to explain radio pulsars if the beam energy can be converted to radio radiation with reasonably high efficiency, but is insufficient to explain pulsed ..gamma..-ray emission from the Crab and other pulsars. In these numerical estimates, we assume that the closedmore » magnetosphere extends to the light cylinder. We also investigate the rotation rate of the plasma, and show that on the open-field lines of the aligned rotator, the beam current induces a twist to the field lines such that an observer at infinity sees the plasma as nonrotating. We apply these results and point out the necessity of including the effects of field-line curvature in a realistic model.« less

A strong infrared source detected in the AFCRL sky survey is confirmed, and is identified with the binary star HD 44179, embedded in a peculiar nebula. UBVRI and broad-band photometry between 2.2 and 27 microns are combined with blue, red, and near-infrared spectra, polarimetry and spectrophotometry of the star, and a range of direct and image-tube photographs of the nebula, to suggest a composite model of the system. In this model, the infrared radiation derives from thermal emission by dust grains contained in a disklike geometry about the central object, which appears to be of spectral type B9-A0 III and which may be in pre-main-sequence evolution. Two infrared emission features are found, peaking at 8.7 and 11.3 microns, the latter corresponding to the feature seen in the spectrum of the planetary nebula NGC 7027. The complex nebular structure is discussed on the basis of photographs through narrow-band continuum and emission-line filters. The polarization data support the suggestion of a disk containing some large particles. No radio continuum emission is detected.

The paper calculates the acceleration of a nonneutral stream of charged particles from the surface of an isolated rotating magnetized neutron star in the case where the particle stream flows along the open field lines of a curved poloidal magnetic field. It is shown that very large electrostatic potential drops can occur in steady unidirectional space-charge-limited flow along the curved open field lines. The explicit incorporation of magnetic field line curvature is the essential element leading to this new result, assuming that all the charges are supplied by emission from the surface. It is emphasized that the current flow and charge density are unique if all of the assumptions are met, with the result that the accelerating electric field near the stellar surface is quite small compared to the vacuum field.