Poynting flux transport channels formed in polar cap regions of neutron star magnetospheres

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F24%3A00138323" target="_blank" >RIV/00216224:14310/24:00138323 - isvavai.cz</a>

Result on the web

<a href="https://ui.adsabs.harvard.edu/abs/2024A%26A...691A.137B/abstract" target="_blank" >https://ui.adsabs.harvard.edu/abs/2024A%26A...691A.137B/abstract</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202450949" target="_blank" >10.1051/0004-6361/202450949</a>

Result language

angličtina

Original language name

Poynting flux transport channels formed in polar cap regions of neutron star magnetospheres

Original language description

Context. Pair cascades in polar cap regions of neutron stars are considered to be an essential process in various models of coherent radio emissions of pulsars. The cascades produce pair plasma bunch discharges in quasi-periodic spark events. The cascade properties, and therefore also the coherent radiation, depend strongly on the magnetospheric plasma properties and vary significantly across and along the polar cap. Importantly, where the radio emission emanates from in the polar cap region is still uncertain. Aims. We investigate the generation of electromagnetic waves by pair cascades and their propagation in the polar cap for three representative inclination angles of a magnetic dipole, 0°, 45°, and 90°. Methods. We use two-dimensional particle-in-cell simulations that include quantum-electrodynamic pair cascades in a charge-limited flow from the star surface. Results. We find that the discharge properties are strongly dependent on the magnetospheric current profile in the polar cap and that transport channels for high intensity Poynting flux are formed along magnetic field lines where the magnetospheric currents approach zero and where the plasma cannot carry the magnetospheric currents. There, the parallel Poynting flux component is efficiently transported away from the star and may eventually escape the magnetosphere as coherent radio waves. The Poynting flux decreases with increasing distance from the star in regions of high magnetospheric currents. Conclusions. Our model shows that no process of energy conversion from particles to waves is necessary for the coherent radio wave emission. Moreover, the pulsar radio beam does not have a cone structure; rather, the radiation generated by the oscillating electric gap fields directly escapes along open magnetic field lines in which no pair creation occurs.

Czech name

—

Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

—

Continuities

S - Specificky vyzkum na vysokych skolach

Publication year

2024

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Astronomy and Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Volume of the periodical

691

Issue of the periodical within the volume

November

Country of publishing house

FR - FRANCE

Number of pages

18

Pages from-to

1-18

UT code for WoS article

001350686200005

EID of the result in the Scopus database

2-s2.0-85208685699