The formation and dissipation of electrostatic shock waves: the role of ion–ion acoustic instabilities

Zhang, W. S.; Cai, Hong-bo; Zhu, Shaoping

doi:10.1088/1361-6587/aab175

Cited by 11 publications

(8 citation statements)

References 46 publications

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“…Our simulations show that this relative drift is driven by the E TNSA in the upstream plasma which results in slower moving heavier ions with low hZ=Ai and faster moving protons with high hZ=Ai. Simulations done by Zhang [26] have shown that in the transverse size-reduced simulation EITI propagates in the x-direction, whereas in the large transverse size simulation it propagates obliquely. In our case, since the propagation directions of EITI are in the x-direction both for the small and the large transversesize simulations [Figs.…”

Section: A Collisionless Shock Formationmentioning

confidence: 99%

“…This leads to the excitation of an electrostatic ion two-stream instability (EITI) [23], which in turn enhances the number of the shockaccelerated protons [24]. To our best knowledge, most of the previous work has focused on shock formation [25][26][27] and ion heating [28][29][30]. This paper is the first investigation on the material (or hZ=Ai) dependence of EITI on CSA.…”

Section: Introductionmentioning

confidence: 99%

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Enhancement of collisionless shock ion acceleration by electrostatic ion two-stream instability in the upstream plasma

Kumar

Sakawa

Döhl

et al. 2019

Phys. Rev. Accel. Beams

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Ion acceleration in electrostatic collisionless shocks is driven by the interaction of the high-power laser with specially tailored near-relativistic critical density plasma. 2D EPOCH particle-in-cell simulations show that the ion acceleration is dependent on the target material used. In materials with low charge-tomass ratio hZ=Ai, proton beams with high flux and low energy spread are generated. In multi-ion plasmas the ions with different hZ=Ai acquire different velocities under a non-oscillating component of electrostatic field in the upstream region. This relative drift between the protons (hZ=Ai ¼ 1) and the lower hZ=Ai ions leads to the excitation of electrostatic ion two-stream instability. This in turn generates a low-velocity component in the upstream expanding protons. The velocity distribution of the upstream expanding protons is further broadened toward the higher velocity by the electrostatic ion two-stream instability between reflected protons, which results in large number of protons being accelerated by the shock.

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Section: A Collisionless Shock Formationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Enhancement of collisionless shock ion acceleration by electrostatic ion two-stream instability in the upstream plasma

Kumar

Sakawa

Döhl

et al. 2019

Phys. Rev. Accel. Beams

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“…Counter-beaming plasma systems are of particular interest in astrophysical and experimental setups [18][19][20][21], i.e., in fusion and plasma experiments the interest is to avoid the formation of escaping beams and stabilize plasma systems, while in astrophysics plasma beams are widely invoked, likely, at the origin of various emissions and fluctuations which trigger their relaxation [22][23][24]. Energetic beams with speed exceeding the mean thermal speed are highly susceptible to electrostatic instabilities [25], and the electromagnetic modes may only hardly compete in nonrelativistic conditions [9].…”

Section: Introductionmentioning

confidence: 99%

A firehose-like aperiodic instability of the counter-beaming electron plasmas

Lopez¹,

Lazar²,

Shaaban³

et al. 2020

Plasma Phys. Control. Fusion

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Depending on the physical conditions involved the beam plasma systems may reveal new unstable regimes triggered by the wave instabilities of different nature. We show through linear theory and numerical simulations the existence of an aperiodic electromagnetic instability which solely develops and control the stability of two symmetric plasma populations counter-moving along the regular magnetic field with a relative drift, v d , small enough to not exceed the particle thermal speed, αe. Emerging at highly oblique angles this mode resembles properties of the aperiodic firehose instability driven by temperature anisotropy. The high growth rates achieved with increasing the relative drift or/and decreasing the plasma beta parameter lead to significant saturation levels of the fluctuating magnetic field power, which explain the relative fast relaxation of electrons. For v d > αe this instability can coexist with the electrostatic two-stream instability, dominating the long-term dynamics of the plasma as soon as v d has relaxed to values smaller than the thermal speed.

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“…However, this shielding is not perfect because of electron thermal motions, resulting potentials of the order of kT e /e ∼ kV can leak out [23], as shown in figure 3 (the three curves in blue, red, and black). On the other hand, the formation of the fine-structure electric field behind the shock front is due to the ion-ion acoustic instability [24]. The upstream ions have been decelerated to subsonic velocities after being transmitted into the downstream region in this process.…”

Section: Electrostatic Shock Generation Due To the MIX Of Au-he Plasmamentioning

confidence: 99%

Anomalous mix induced by a collisionless shock wave in an inertial confinement fusion hohlraum

Yan¹,

Cai²,

Zhang³

et al. 2019

Nucl. Fusion

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The anomalous mix at the high-Z and low-Z plasma interfaces in an inertial confinement fusion hohlraum is a current topic of interest. The mechanism for such an anomalous mix in the interpenetration layer at the high-Z and low-Z plasma interface and its effects on the laser plasma instabilities have been investigated by particle-in-cell simulations. It is found that a diffusion-driven collisionless shock wave can be generated from an initially sharp high-Z and low-Z plasma interface with total pressure balance and constant temperature in the laser propagation channel. This purely electrostatic shock wave propagates into the high-Z plasma and leads to mix of different species of ions which is significantly faster than a classical mix in the presence of the large electric field. The mix layer width, measured as a separation distance affected by the shock, grows as δd ∝ t α , where α ∼ 1. The effect of the anomalous mix on the linear growth rate of laser plasma instabilities is evaluated.

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The formation and dissipation of electrostatic shock waves: the role of ion–ion acoustic instabilities

Cited by 11 publications

References 46 publications

Enhancement of collisionless shock ion acceleration by electrostatic ion two-stream instability in the upstream plasma

Enhancement of collisionless shock ion acceleration by electrostatic ion two-stream instability in the upstream plasma

A firehose-like aperiodic instability of the counter-beaming electron plasmas

Anomalous mix induced by a collisionless shock wave in an inertial confinement fusion hohlraum

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