Neutrino beam plasma instability

We derive relativistic fluid set of equations for neutrinos and electrons from relativistic Vlasov equations with Fermi weak interaction force. Using these fluid equations, we obtain a dispersion relation describing neutrino beam plasma instability, which is little different from normal dispersion relation of streaming instability. It contains new, nonelectromagnetic, neutrino-plasma (or electroweak) stable and unstable modes also. The growth of the instability is weak for the highly relativistic neutrino flux, but becomes stronger for weakly relativistic neutrino flux in the case of parameters appropriate to the early universe and supernova explosions. However, this mode is dominant only for the beam velocity greater than 0.25c and in the other limit electroweak unstable mode takes over.     

Observation of the parametric two-ion decay instability with thomson scattering

We present the first direct experimental observation of the parametric two-ion decay instability of ion-acoustic waves driven by a high intensity (5 x 10(15) W cm(-2)) laser beam in a laser produced high-Z plasma. Using two separate Thomson scattering diagnostics simultaneously, we directly measure the scattering from thermal ion-acoustic fluctuations, the primary ion waves that are driven to large amplitudes by the high intensity beam, and the two-ion decay products. The decay products are shown to be present only where the interaction takes place and their k spectrum is broad.     

Oscillating two-stream instability of a plasma wave in a plasmachannel

A long wavelength Langmuir wave (ω₀, k₀), propagating through a parabolic plasma density channel, can decay into a low-frequency mode (ω,k&oarr;) and two short wavelength Langmuir wave sidebands (ν_1,2,k&oarr;_1,2 ), via two-stream instability where ω_1,2=ω∓ω₀ and k&oarr;_1,2=k&oarr;∓k&oarr;₀. Depending on the mode number n, the growth rate maximizes in the range γ_max≃0.1ω_pi-0.4ω_pi for the range of k from 0.1(ω_pi/c_s) to 0.2(ω_pi/c_x) for ν₀~ν_th where ν₀ and ν_th are the oscillatory and thermal velocities of electrons, ω_pi is the ion plasma frequency on the axis, and c_s is the sound speed. The growth rate increases with the width a of the plasma density channel. It decreases with the mode number. The instability may be relevant to laser based charged particle accelerators     

Hose instability of a beam of charged particles penetrating a plasma

Employing the phenomenological approach, the dispersion relation for the “hose” instability of a beam of charged particles passing through a plasma has been presented. Energy transfer from the beam is considered. Also, the behavior of the hose instability amplitude under various plasma conditions is discussed in detail.     

Observation of beam instability in the SSRF storage ring

During the SSRF(Shanghai Synchrotron Radiation Facility) storage ring phase-I commissioning, some instabilities have been observed, and the broadband impedance has also been measured. The primary instabilities at present stage are vertical beam blow up and resistive wall instability.     

Observation of beam instability in the SSRF storage ring

During the SSRF(Shanghai Synchrotron Radiation Facility) storage ring phase-I commissioning, some instabilities have been observed, and the broadband impedance has also been measured. The primary instabilities at present stage are vertical beam blow up and resistive wall instability.     

On the quantum theory of beam instability in plasma

The quantum theory of induced Cherenkov radiation by an electron beam of longitudinal waves in isotropic plasma is presented. Nonrelativistic quantum nonlinear equations of Cherenkov beam-plasma instability are obtained. A quantum dispersion relation is derived in the linear approximation and instability development increments are determined.     

Effect of self-generated magnetic field on the two-plasmon decay instability in a laser-produced plasma

Summary In this paper we have made a theoretical investigation on the two-plasmon decay instability of laser radiation in the presence of the selfgenerated magnetic field at the quarter-critical density region in a laserproduced plasma. The Vlasov equation in terms of guiding centre coordinates has been employed to obtain the nonlinear response of electrons in the plasma. The threshold power density of the incident laser radiation for the two-plasmon decay instability is always exceeded in currently employed power densities in laser-target experiments and above the threshold the growth rate of the instability is quite large. It is also noticed that the selfgenerated magnetic field enhances the threshold to a large extent, thus drastically reducing the growth rate of the instability. To speed up publication, the author of this paper has agreed to not receive the proofs for correction     

Large-scale resistive instability of a relativistic electron beam in a plasma channel

The kinetic equation method is used to study the stability of a heavy-current electron beam in a dense plasma channel with a relatively low conductivity. Increments and critical currents are obtained. It is shown that even slightly nonlinear transverse motion stabilizes the system. The main conclusions agree with the experimental results.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 84–89, April, 1986.     

Oscillating two-stream instability of a lower hybrid wave in aninhomogenous plasma

The effect of the density inhomogeneity on the oscillating two-stream instability of a lower hybrid pump wave with a finite wavelength is investigated. The density inhomogeneity introduces dephasing that restricts the interaction region where the matching conditions hold. The loss of energy due to convection from this region introduces a certain convection threshold for the onset of this instability. The coupled differential equations are solved in Fourier space by converting them into an uncoupled eigenvalue equation and then applying a quantization condition. Expressions are obtained for the growth rate and the convective threshold, and the results are applied to the Princeton Large Torus parameters     

On a new scenario for the saturation of the low-threshold two-plasmon parametric decay instability of an extraordinary wave in the inhomogeneous plasma of magnetic traps

The most probable scenario for the saturation of the low-threshold two-plasmon parametric decay instability of an electron cyclotron extraordinary wave has been analyzed. Within this scenario two upperhybrid plasmons at frequencies close to half the pump wave frequency radially trapped in the vicinity of the local maximum of the plasma density profile are excited due to the excitation of primary instability. The primary instability saturation results from the decays of the daughter upper-hybrid waves into secondary upperhybrid waves that are also radially trapped in the vicinity of the local maximum of the plasma density profile and ion Bernstein waves.     

Effect of nonmonochromaticity of pump wave on decay instabilities in a plasma

Radiophysics and Quantum Electronics -     

Decay instability of lower hybrid wave in a cold homogeneous plasma

We have pointed out the possibility of parametric excitation of a low frequency wave, propagating almost perpendicular to the magnetic field in a cold homogeneous plasma, by a lower hybrid pump wave. The growth rate and threshold power are calculated.