The effect of shear flow and the density gradient on the Weibel instability growth rate in the dense plasma

In the field of fast ignition scheme, self‐generated magnetic fields via beam resistive filamentation have a significant role in the angular divergence of the relativistic electron beam, which can be affected by the intensity of other self‐generated magnetic fields. In this context, the effects of pressure gradient sources arising from temperature and density gradient of the pellet along the beam flow direction are investigated. The results showed that the resistive filamentation instability can be strongly amplified compared to the fully homogeneous plasma. In this respect, for the distance away from the critical surface, the instability is protected for a longer wave number. Also, the beam and plasma properties such as the beam relativistic factor, the beam number density, and the degree of the plasma temperature anisotropy might be effective.

\begin{array}{l} f_{0} = \frac{{false(m_{0} γ_{b} false)}^{\frac{3}{2}} η^{\frac{1}{2}}}{{false(2 π false)}^{\frac{3}{2}} T_{⊥}^{b} {false(T_{z}^{b} false)}^{\frac{1}{2}}} \exp ((), - \frac{m_{0} γ_{b} (v_{x}^{2} + v_{y}^{2})}{2 T_{⊥}^{b}} - \frac{m_{0} γ_{b} {false(v_{z} - V_{b} false)}^{2} η}{2 T_{z}^{b}}) \\ + \frac{{false(m_{0} false)}^{\frac{3}{2}} η^{\frac{1}{2}}}{{false(2 π false)}^{\frac{3}{2}} T_{⊥}^{p} {false(T_{z}^{p} false)}^{\frac{1}{2}}} \exp ((), - \frac{m_{0} (v_{x}^{2} + v_{y}^{2})}{2 T_{⊥}^{p}} - \frac{m_{0} {false(v_{z} + V_{p} false)}^{2} η}{2 T_{z}^{p}}) \end{array}

where

T_{b}

and

T_{p}

introduce the temperature of the electron beam, and the electron returned current, respectively. The index

⊥

labels direction normal to the beam flow direction and

γ_{b} = ((), 1<...>)

…”

Section: Theorymentioning

confidence: 99%

A study of the effect of self‐generated pressure gradient sources on the resistive filamentation instability

Mahdavi

Khanzadeh

2021

“…It makes the energy transport effectiveness very poor, and the fast electrons cannot transport beyond the filament length. [26][27][28][29] In the turbulence state of plasma, the electron beams deposit most of their energy in a reasonably short-flat density region. The stress and viscosity affect convective flow in heat losses that lead to increasing anisotropic temperatures.…”

Section: Introductionmentioning

confidence: 99%

The anisotropic plasma wave in the plasma turbulence

Azadboni

2022

In this paper, the influence of plasma turbulence due to the sheared and body stress flow on the dispersion characteristics of the transverse electromagnetic modes in strongly coupled plasma is analysed. Using kinetic theory and solving the scattering relationship for the Vlasov‐Maxwell system, the influence of plasma turbulence on the growth of the electromagnetic mode is investigated. The minimum value of the stress rate threshold for the growth rate of electromagnetic instability in the linear polarization is higher than that of circular polarization. It is shown that the instability growth rate maximum for the circular polarization is about 100 times higher than that of the linear polarization. In the circular polarization, the value minimum of the shear stress is 1.2 times the minimum volume of the body stress. For the linear polarization, the value minimum of the body stress is 1.5 times the minimum volume of the shear stress. Increasing the density gradient of plasma leads to a higher stress threshold rate, and the range of propagation angles of growing modes is limited. With increasing steps of the density gradient plasma in the low‐density corona, electromagnetic instability occurs at a higher stress flow.

“…The presence of intense turbulence in plasmas leads to the modification of their physical properties as they induce anisotropy owing to the privileged direction of stress flow. [ 38,39 ] Turbulent and stress effects significant damp small‐scale velocity structures. Stress flow can be expected in the imploding target plasma of ICF.…”

Section: Introductionmentioning

confidence: 99%

Study of Coulomb collisional effects on the propagation of electromagnetic waves in a turbulent plasma

Azadboni

2020

The presence of Weibel instability in laser-irradiated fuel could be detrimental to the process of ablative implosion, which is necessary for achieving thermonuclear fusion reactions. In this paper, the effect of the Coulomb collisional within the turbulent plasma on the Weibel instability growth rate has been investigated for linear and circular polarization. The results indicate that the Weibel instability growth rate at circular polarization near the ignition centre of the fuel fusion (collisional plasma) is about 10 5 times higher than the collisional Weibel instability growth rate at linear polarization. The Weibel instability growth rate is observed near the critical density of the fuel fusion (collisionless plasma) at linear polarization and enhancement near the foot of the heat in front of the fuel fusion. By increasing the steps of the density gradient plasma in the low-density corona, electromagnetic instability occurs at a higher stress flow. Therefore, the deposition condition of electron beam energy in circular polarization of turbulent plasma can be shifted to the fuel core for suitable ignition.