ON PLASMA ROTATION AND DRIFTING SUBPULSES IN PULSARS: USING ALIGNED PULSAR B0826-34 AS A VOLTMETER
- Netherlands Institute for Radio Astronomy (ASTRON), Postbus 2, 7990 AA Dwingeloo (Netherlands)
We derive the exact drift velocity of plasma in the pulsar polar cap, in contrast to the order-of-magnitude expressions presented by Ruderman and Sutherland and generally used throughout the literature. We emphasize that the drift velocity depends not on the absolute value, as is generally used, but on the variation of the accelerating potential across the polar cap. If we assume that drifting subpulses in pulsars are indeed due to this plasma drift, several observed subpulse-drift phenomena that are incompatible with the Ruderman and Sutherland family of models can now be explained: we show that variations of drift rate, outright drift reversals, and the connection between drift rates and mode changes have natural explanations within the frame of the 'standard' pulsar model, when derived exactly. We apply this model for drifting subpulses to the case of PSR B0826-34, an aligned pulsar with two separate subpulse-drift regions emitted at two different colatitudes. Careful measurement of the changing and reversing drift rate in each band independently sets limits on the variation of the accelerating potential drop. The derived variation is small, {approx}10{sup -3} times the vacuum potential drop voltage. We discuss the implications of this result for pulsar modeling.
- OSTI ID:
- 22036980
- Journal Information:
- Astrophysical Journal, Vol. 752, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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