Time-dependent pair cascades in magnetospheres of neutron stars - I. Dynamics of the polar cap cascade with no particle supply from the neutron star surface

By A. N. Timokhin. 2010

161 citations recorded by the source corpus.

I argue that the problem of electromagnetically driven electron–positron cascades in magnetospheres of neutron stars must be addressed starting from first principles. I describe a general numerical algorithm for doing self-consistent kinetic simulations of electron–positron cascades – wherein particle acceleration, pair creation and screening of the electric field are calculated simultaneously – and apply it to model the Ruderman & Sutherland cascade in one dimension. I find that pair creation is quite regular and quasi-periodic. In each cycle a blob of ultra-relativistic electron–positron plasma is generated; it propagates into the magnetosphere leaving a tail of less relativistic plasma behind, and the next discharge occurs when this mildly relativistic plasma leaves the polar cap. A short burst of pair formation is followed by a longer quiet phase when accelerating electric field is screened and no pairs are produced. Some of freshly injected electron–positrons pairs get trapped in plasma oscillations creating a population of low-energy particles. The cascade easily adjusts to the current density required by the pulsar magnetosphere by reversing some of the low-energy particles. Each discharge generates a strong coherent superluminal electrostatic wave, which may be relevant for the problem of pulsar radioemission.

Subfields: Astronomy and Astrophysics, Geophysics, Ocean Engineering

View Paper: https://www.semanticscholar.org/paper/3b06f27b73b4802991776d5e361c28e257c67963

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. J. Arons
2. Don B. Melrose
3. A. N. Timokhin
4. A. Spitkovsky
5. A. Philippov
6. L. Sironi
7. Xue-Ning Bai

In Geophysics

1. J. Arons
2. Don B. Melrose
3. A. N. Timokhin
4. A. Spitkovsky
5. Xue-Ning Bai

In Ocean Engineering

1. Don B. Melrose
2. J. Arons
3. A. N. Timokhin

Citations in the corpus

• Current flow and pair creation at low altitude in rotation-powered pulsars’ force-free magnetospheres: space charge limited flow (2012, methodology): “The opposite case, with complete suppression of particle emission from the surface, was studied in Timokhin (2010), a realization of the scenario conjectured by Ruderman & Sutherland (1975).”
• Coherent emission mechanisms in astrophysical plasmas (2017, background): “An alternative model in which charges from the surface play no role, with pair creation being the only source of plasma in the magnetosphere (Timokhin, 2010), seems plausible.”