The Emission of Electromagnetic Waves during the Coalescence of Two Parallel Current Loops in Solar Flares

Saito, Shinji; Sakai, Jun–ichi

doi:10.1086/426788

Cited by 14 publications

(7 citation statements)

References 11 publications

(11 reference statements)

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“…To simulate the processes under study, we use a 2.5-D (2D3V -2 spatial and 3 velocity components) fully relativistic electromagnetic particle-in-cell (PIC) code (Saito & Sakai 2004). The system size is L x = 4000Δ and L y = 600Δ, where Δ (=1) is a grid size.…”

Section: Modelmentioning

confidence: 99%

Radio spectra generated during coalescence processes of plasmoids in a flare current sheet

Karlický

Bárta

Rybák

2010

A&A

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Aims. Motivated by observations of the drifting pulsating structures (DPSs) in solar radio spectra, we study the electromagnetic (radio) emission generated during tearing and coalescence processes in a flare current sheet. Methods. For numerical simulations, we used a 2.5-D particle-in-cell electromagnetic relativistic code. Numerical data were analyzed by the wavelet methods. Results. It is found that the electromagnetic emission is generated during a coalescence of plasmoids, and it has a quasi-periodic character. Detailed analysis reveals that the electromagnetic emission is produced around the interacting plasmoids just before their coalescence into a larger one. The period in variations of electromagnetic emission corresponds to that of magnetic field at the same region. Reflections of the electromagnetic waves between interacting plasmoids are recognized. The computed and observed periodicities are discussed. The similarity of the DPSs with some radio bursts observed during star flares indicates a broader applicability for this model.

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Section: Modelmentioning

confidence: 99%

Radio spectra generated during coalescence processes of plasmoids in a flare current sheet

Karlický

Bárta

Rybák

2010

A&A

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“…To simulate the processes under study, we used a 2.5D (2D3V − 2 spatial and 3 velocity components) fully relativistic electromagnetic particle-in-cell code (Saito & Sakai 2004). The system size is L x = 2000∆ and L y = 600∆, where ∆ (=1) is a grid size.…”

Section: Modelmentioning

confidence: 99%

Drifting pulsating structures generated during tearing and coalescence processes in a flare current sheet

Karlický

Bárta

2007

A&A

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Aims. Based on particle-in-cell simulations, drifting pulsating structures are interpreted as the radio emission generated during tearing and coalescence processes in the current sheet of a flare. Methods. A 2.5D particle-in-cell electromagnetic relativistic code was used considering two versions of the model: a) the model with one current sheet with free boundary conditions and b) the model with two current sheets and periodic boundary conditions. The dispersion diagrams of electromagnetic waves we then constructed using the 2D Fourier transform. Results. It is found that electrons are accelerated most efficiently in the region near the x-point of the magnetic field structure in the phase at the end of tearing process and at the beginning of plasmoid coalescence. The most energetic electrons are distributed mainly along the x-lines of the magnetic field structure. During these processes, Langmuir waves are generated, along with the electromagnetic (radio) ones. It looks as these electromagnetic waves can be observed mainly on the second harmonics of the plasma frequencies corresponding to the plasma densities in the external parts of the plasmoids.

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“…They found that electrostatic waves called electron Bernstein waves (EBWs) excited in the current sheet were converted to the fast extraordinary (X) wave (FXW) through a linear mode conversion process during the merging of current loops. 9 The converted X waves propagated outward from the current loops, which is considered as the observed radio waves mentioned in the above F arn ık's report.…”

Section: Introductionmentioning

confidence: 91%

“…The radiation process of the EM waves originated from the EBW emission (EBE) considering the linear mode conversion, reflection, and tunneling effects was theoretically studied for decades [11][12][13] and the quantitative unified description of the relationships between the waves including the EBW and EM waves, which propagate inward and outward to the UHR with any propagation angles was given by Igami et al with considering those effects. 14 In laboratory experiments 15,16 and simulation study, 9 FXWs originated from EBWs are often observed. The principle of these observations is also based on the thermal radiation of electrons.…”

Section: Introductionmentioning

confidence: 99%

Excitation of electrostatic waves in the electron cyclotron frequency range during magnetic reconnection in laboratory overdense plasmas

Kuwahata¹,

Igami²,

Kawamori³

et al. 2014

Physics of Plasmas

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We report the observation of electromagnetic radiation at high harmonics of the electron cyclotron frequency that was considered to be converted from electrostatic waves called electron Bernstein waves (EBWs) during magnetic reconnection in laboratory overdense plasmas. The excitation of EBWs was attributed to the thermalization of electrons accelerated by the reconnection electric field around the X-point. The radiative process discussed here is an acceptable explanation for observed radio waves pulsation associated with major flares. V C 2014 AIP Publishing LLC.

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The Emission of Electromagnetic Waves during the Coalescence of Two Parallel Current Loops in Solar Flares

Cited by 14 publications

References 11 publications

Radio spectra generated during coalescence processes of plasmoids in a flare current sheet

Radio spectra generated during coalescence processes of plasmoids in a flare current sheet

Drifting pulsating structures generated during tearing and coalescence processes in a flare current sheet

Excitation of electrostatic waves in the electron cyclotron frequency range during magnetic reconnection in laboratory overdense plasmas

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