Saturation of the Filamentation Instability and Dispersion Measure of Fast Radio Bursts
Nonlinear effects are crucial for the propagation of fast radio bursts (FRBs) near the source. We study the filamentation of FRBs in the relativistic winds of magnetars, which are commonly invoked as the most natural FRB progenitors. As a result of filamentation, the particle number density and radi...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal Letters |
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| Online Access: | https://doi.org/10.3847/2041-8213/acb260 |
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| author | Emanuele Sobacchi Yuri Lyubarsky Andrei M. Beloborodov Lorenzo Sironi Masanori Iwamoto |
| author_facet | Emanuele Sobacchi Yuri Lyubarsky Andrei M. Beloborodov Lorenzo Sironi Masanori Iwamoto |
| author_sort | Emanuele Sobacchi |
| collection | DOAJ |
| description | Nonlinear effects are crucial for the propagation of fast radio bursts (FRBs) near the source. We study the filamentation of FRBs in the relativistic winds of magnetars, which are commonly invoked as the most natural FRB progenitors. As a result of filamentation, the particle number density and radiation intensity develop strong gradients along the direction of the wind magnetic field. A steady state is reached when the plasma pressure balances the ponderomotive force. In such a steady state, particles are confined in periodically spaced thin sheets, and electromagnetic waves propagate between them as in a waveguide. We show the following. (i) The dispersion relation resembles that in the initial homogeneous plasma, but the effective plasma frequency is determined by the separation of the sheets, not directly by the mean particle density. (ii) The contribution of relativistic magnetar winds to the dispersion measure of FRBs could be several orders of magnitude larger than previously thought. The dispersion measure of the wind depends on the properties of individual bursts (e.g., the luminosity) and therefore can change significantly among different bursts from repeating FRBs. (iii) Induced Compton scattering is suppressed because most of the radiation propagates in near-vacuum regions. |
| first_indexed | 2024-03-12T04:43:57Z |
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| id | doaj.art-664e41bb921a41a59dc6d513d3248fc5 |
| institution | Directory Open Access Journal |
| issn | 2041-8205 |
| language | English |
| last_indexed | 2024-03-12T04:43:57Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal Letters |
| spelling | doaj.art-664e41bb921a41a59dc6d513d3248fc52023-09-03T09:30:34ZengIOP PublishingThe Astrophysical Journal Letters2041-82052023-01-019432L2110.3847/2041-8213/acb260Saturation of the Filamentation Instability and Dispersion Measure of Fast Radio BurstsEmanuele Sobacchi0Yuri Lyubarsky1https://orcid.org/0000-0002-2316-8899Andrei M. Beloborodov2https://orcid.org/0000-0001-5660-3175Lorenzo Sironi3https://orcid.org/0000-0002-1227-2754Masanori Iwamoto4https://orcid.org/0000-0003-2255-5229Department of Astronomy and Columbia Astrophysics Laboratory, Columbia University , New York, NY 10027, USA ; emanuele.sobacchi@mail.huji.ac.il; Racah Institute for Physics, The Hebrew University , Jerusalem 91904, IsraelPhysics Department, Ben-Gurion University , P.O.B. 653, Beer-Sheva 84105, IsraelPhysics Department and Columbia Astrophysics Laboratory, Columbia University , 538 West 120th Street, New York, NY 10027, USA; Max Planck Institute for Astrophysics , Karl-Schwarzschild-Str. 1, D-85741, Garching, GermanyDepartment of Astronomy and Columbia Astrophysics Laboratory, Columbia University , New York, NY 10027, USA ; emanuele.sobacchi@mail.huji.ac.ilFaculty of Engineering Sciences, Kyushu University , 6-1, Kasuga-koen, Kasuga, Fukuoka, 816-8580, JapanNonlinear effects are crucial for the propagation of fast radio bursts (FRBs) near the source. We study the filamentation of FRBs in the relativistic winds of magnetars, which are commonly invoked as the most natural FRB progenitors. As a result of filamentation, the particle number density and radiation intensity develop strong gradients along the direction of the wind magnetic field. A steady state is reached when the plasma pressure balances the ponderomotive force. In such a steady state, particles are confined in periodically spaced thin sheets, and electromagnetic waves propagate between them as in a waveguide. We show the following. (i) The dispersion relation resembles that in the initial homogeneous plasma, but the effective plasma frequency is determined by the separation of the sheets, not directly by the mean particle density. (ii) The contribution of relativistic magnetar winds to the dispersion measure of FRBs could be several orders of magnitude larger than previously thought. The dispersion measure of the wind depends on the properties of individual bursts (e.g., the luminosity) and therefore can change significantly among different bursts from repeating FRBs. (iii) Induced Compton scattering is suppressed because most of the radiation propagates in near-vacuum regions.https://doi.org/10.3847/2041-8213/acb260Radio transient sourcesPlasma astrophysics |
| spellingShingle | Emanuele Sobacchi Yuri Lyubarsky Andrei M. Beloborodov Lorenzo Sironi Masanori Iwamoto Saturation of the Filamentation Instability and Dispersion Measure of Fast Radio Bursts The Astrophysical Journal Letters Radio transient sources Plasma astrophysics |
| title | Saturation of the Filamentation Instability and Dispersion Measure of Fast Radio Bursts |
| title_full | Saturation of the Filamentation Instability and Dispersion Measure of Fast Radio Bursts |
| title_fullStr | Saturation of the Filamentation Instability and Dispersion Measure of Fast Radio Bursts |
| title_full_unstemmed | Saturation of the Filamentation Instability and Dispersion Measure of Fast Radio Bursts |
| title_short | Saturation of the Filamentation Instability and Dispersion Measure of Fast Radio Bursts |
| title_sort | saturation of the filamentation instability and dispersion measure of fast radio bursts |
| topic | Radio transient sources Plasma astrophysics |
| url | https://doi.org/10.3847/2041-8213/acb260 |
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