Electrodynamics and Radiation from Rotating Neutron Star Magnetospheres
Neutron stars are compact objects rotating at high speed, up to a substantial fraction of the speed of light (up to 20% for millisecond pulsars) and possessing ultra-strong electromagnetic fields (close to and sometimes above the quantum critical field of 4.4 <inline-formula> <math display=...
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| Format: | Article |
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MDPI AG
2020-01-01
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| Series: | Universe |
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| Online Access: | https://www.mdpi.com/2218-1997/6/1/15 |
| _version_ | 1818035383358717952 |
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| author | Jérôme Pétri |
| author_facet | Jérôme Pétri |
| author_sort | Jérôme Pétri |
| collection | DOAJ |
| description | Neutron stars are compact objects rotating at high speed, up to a substantial fraction of the speed of light (up to 20% for millisecond pulsars) and possessing ultra-strong electromagnetic fields (close to and sometimes above the quantum critical field of 4.4 <inline-formula> <math display="inline"> <semantics> <mrow> <mo>×</mo> <mspace width="3.33333pt"></mspace> <msup> <mn>10</mn> <mn>9</mn> </msup> </mrow> </semantics> </math> </inline-formula> <inline-formula> <math display="inline"> <semantics> <mi mathvariant="normal">T</mi> </semantics> </math> </inline-formula>). Moreover, due to copious <inline-formula> <math display="inline"> <semantics> <msup> <mi>e</mi> <mo>±</mo> </msup> </semantics> </math> </inline-formula> pair creation within the magnetosphere, the relativistic plasma surrounding the star is forced into corotation up to the light cylinder where the corotation speed reaches the speed of light. The neutron star electromagnetic activity is powered by its rotation which becomes relativistic in the neighborhood of this light cylinder. These objects naturally induce relativistic rotation on macroscopic scales about several thousands of kilometers, a crucial ingredient to trigger the central engine as observed on Earth. In this paper, we elucidate some of the salient features of this corotating plasma subject to efficient particle acceleration and radiation, emphasizing several problems and limitations concerning current theories of neutron star magnetospheres. Relativistic rotation in these systems is indirectly probed by the radiation produced within the magnetosphere. Depending on the underlying assumptions about particle motion and radiation mechanisms, different signatures on their light curves, spectra, pulse profiles and polarization angles are expected in their broadband electromagnetic emission. We show that these measurements put stringent constraints on the way to describe particle electrodynamics in a rotating neutron star magnetosphere. |
| first_indexed | 2024-12-10T06:54:11Z |
| format | Article |
| id | doaj.art-afee8ed071354d8cbb3731ba73232eea |
| institution | Directory Open Access Journal |
| issn | 2218-1997 |
| language | English |
| last_indexed | 2024-12-10T06:54:11Z |
| publishDate | 2020-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Universe |
| spelling | doaj.art-afee8ed071354d8cbb3731ba73232eea2022-12-22T01:58:28ZengMDPI AGUniverse2218-19972020-01-01611510.3390/universe6010015universe6010015Electrodynamics and Radiation from Rotating Neutron Star MagnetospheresJérôme Pétri0Observatoire Astronomique de Strasbourg, CNRS, Université de Strasbourg, UMR 7550, F-67000 Strasbourg, FranceNeutron stars are compact objects rotating at high speed, up to a substantial fraction of the speed of light (up to 20% for millisecond pulsars) and possessing ultra-strong electromagnetic fields (close to and sometimes above the quantum critical field of 4.4 <inline-formula> <math display="inline"> <semantics> <mrow> <mo>×</mo> <mspace width="3.33333pt"></mspace> <msup> <mn>10</mn> <mn>9</mn> </msup> </mrow> </semantics> </math> </inline-formula> <inline-formula> <math display="inline"> <semantics> <mi mathvariant="normal">T</mi> </semantics> </math> </inline-formula>). Moreover, due to copious <inline-formula> <math display="inline"> <semantics> <msup> <mi>e</mi> <mo>±</mo> </msup> </semantics> </math> </inline-formula> pair creation within the magnetosphere, the relativistic plasma surrounding the star is forced into corotation up to the light cylinder where the corotation speed reaches the speed of light. The neutron star electromagnetic activity is powered by its rotation which becomes relativistic in the neighborhood of this light cylinder. These objects naturally induce relativistic rotation on macroscopic scales about several thousands of kilometers, a crucial ingredient to trigger the central engine as observed on Earth. In this paper, we elucidate some of the salient features of this corotating plasma subject to efficient particle acceleration and radiation, emphasizing several problems and limitations concerning current theories of neutron star magnetospheres. Relativistic rotation in these systems is indirectly probed by the radiation produced within the magnetosphere. Depending on the underlying assumptions about particle motion and radiation mechanisms, different signatures on their light curves, spectra, pulse profiles and polarization angles are expected in their broadband electromagnetic emission. We show that these measurements put stringent constraints on the way to describe particle electrodynamics in a rotating neutron star magnetosphere.https://www.mdpi.com/2218-1997/6/1/15neutron starsmagnetosphereplasmaradiationcorotationelectrodynamics |
| spellingShingle | Jérôme Pétri Electrodynamics and Radiation from Rotating Neutron Star Magnetospheres Universe neutron stars magnetosphere plasma radiation corotation electrodynamics |
| title | Electrodynamics and Radiation from Rotating Neutron Star Magnetospheres |
| title_full | Electrodynamics and Radiation from Rotating Neutron Star Magnetospheres |
| title_fullStr | Electrodynamics and Radiation from Rotating Neutron Star Magnetospheres |
| title_full_unstemmed | Electrodynamics and Radiation from Rotating Neutron Star Magnetospheres |
| title_short | Electrodynamics and Radiation from Rotating Neutron Star Magnetospheres |
| title_sort | electrodynamics and radiation from rotating neutron star magnetospheres |
| topic | neutron stars magnetosphere plasma radiation corotation electrodynamics |
| url | https://www.mdpi.com/2218-1997/6/1/15 |
| work_keys_str_mv | AT jeromepetri electrodynamicsandradiationfromrotatingneutronstarmagnetospheres |