Effect of collisions on the relativistic electromagnetic instability

Okada, Toshio; Niu, Keishiro

doi:10.1017/s0022377800010424

Cited by 40 publications

(23 citation statements)

References 7 publications

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“…The laser pulse drives relativistic currents, compensating return currents, and creates a pattern of counterpropagating currents which are subject to current filamentation instabilities (CFI) including the Weibel mode [3]. In the theoretical arena, numerous versions of analytical and numerical methods have been developed in the past, to explore this type of instabilities [4,5,6,7,8,9,10,11,12,13,14,15,16,17]. In general, the physical mechanism of the electromagnetic CFI is explained as follows: When the compensation of the counterpropagating electron currents is disturbed in the transverse direction, magnetic repulsion between the two currents reinforces the initial disturbance.…”

Section: Introductionmentioning

confidence: 99%

Eigenmodes and growth rates of relativistic current filamentation instability in a collisional plasma

Honda

2004

Phys. Rev. E

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I theoretically found eigenmodes and growth rates of relativistic current filamentation instability in collisional regimes, deriving a generalized dispersion relation from self-consistent beam-Maxwell equations. For symmetrically counterstreaming, fully relativistic electron currents, the collisional coupling between electrons and ions creates the unstable modes of growing oscillation and wave, which stand out for long-wavelength perturbations. In the stronger collisional regime, the growing oscillatory mode tends to be dominant for all wavelengths. In the collisionless limit, those modes vanish, while maintaining another purely growing mode that exactly coincides with a standard relativistic Weibel mode. It is also shown that the effects of electron-electron collisions and thermal spread lower the growth rate of the relativistic Weibel instability. The present mechanisms of filamentation dynamics are essential for transport of homogeneous electron beam produced by the interaction of high power laser pulses with plasma.

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Section: Introductionmentioning

confidence: 99%

Eigenmodes and growth rates of relativistic current filamentation instability in a collisional plasma

Honda

2004

Phys. Rev. E

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“…In the linear stage, filamentation is generally studied under some simplifying ab-initio transverse approximation of the dielectric tensor, so that filamentation instability is attributed to the exponential growth of unstable electromagnetic purely transverse modes (k · E = 0) with wave vector k normal to the beam [4,8,9,10,11,12]. It is also common to refer to this instability as Weibel instability [4,7,8], though the original mode studied by Weibel [13] would require some plasma temperature anisotropy to be driven.…”

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confidence: 99%

Characterization of the Initial Filamentation of a Relativistic Electron Beam Passing through a Plasma

2005

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The linear instability that induces a relativistic electron beam passing through a return plasma current to filament transversely is often related to some filamentation mode with wave vector normal to the beam or confused with Weibel modes. We show that these modes may not be relevant in this matter and identify the most unstable mode on the two-stream/filamentation branch as the main trigger for filamentation. This sets both the characteristic transverse and longitudinal filamentation scales in the non-resistive initial stage.

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“…This means the two stream instability is not so dengerous. The maximum growth rate of the filamentation instability between the beam electrons and the separator electrons is given by (24) …”

Section: Electron Bunch Acceleration By the Tem 10 + Tem 01 Mode Lasementioning

confidence: 99%

Electron Bunch Acceleration by an Intense Laser Pulse with a Plasma Separator

et al. 2005

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MemberWe study an electron acceleration by using a focused TEM 10 + TEM 01 mode laser pulse with a plasma separator in vacuum. By using the TEM 10 + TEM 01 mode laser and the plasma separator, the electrons are accelerated strongly compared with that in the case of a TEM 00 mode laser, and the divergence of the electron bunch accelerated is suppressed in the transverse direction by the transverse ponderomotive force of the laser. In both the TEM 00 mode laser and the TEM 10 + TEM 01 mode laser, the electrons are decelerated by the laser at the deceleration phase of the laser pulse tail. In order to suppress the energy loss, we set an overdense plasma separator before the electrons are decelerated by the laser tail. Only the laser pulse is reflected by the plasma separator, and the high energy electrons pass through the plasma separator without the energy loss at the tail of laser pulse.

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Effect of collisions on the relativistic electromagnetic instability

Cited by 40 publications

References 7 publications

Eigenmodes and growth rates of relativistic current filamentation instability in a collisional plasma

Eigenmodes and growth rates of relativistic current filamentation instability in a collisional plasma

Characterization of the Initial Filamentation of a Relativistic Electron Beam Passing through a Plasma

Electron Bunch Acceleration by an Intense Laser Pulse with a Plasma Separator

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