Energy deposition of fast electrons in dense magnetized plasmas

Yang, X. H.; Xu, Han; Y., Y.; Ge, Z. Y.; Zhuo, H. B.; Shao, F. Q.

doi:10.1063/1.5023779

Cited by 5 publications

(7 citation statements)

References 39 publications

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“…Though it would lead to an enhancement of collisional heating (Q f ∝ n f n e /T 1/2 f ), it is still to be neglected compared to the Ohmic heating (not shown for brevity) and is consistent with that reported in Refs. [9,18,31]. One can see that, in Fig.…”

Section: Resultsmentioning

confidence: 97%

“…In the range of laser and target parameters of our interest, the dominant energy deposition term in Eq. ( 6b) is Ohmic heating [9,18,31], and quasi-neutrality is a good approximation, i.e., J b ≃ − J f . Thus the background electron energy equation becomes…”

Section: Resultsmentioning

confidence: 99%

“…The filamentation of fast electrons is also mitigated in the doped targets. The paper is organized as follow: Section II describes the physical model employed in the hybrid PIC/fluid code HEETS [17,18]. Section III shows the transport parameter models used in the work.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Control of fast electron propagation in foam target by high-Z doping

Xu¹,

Yang²,

Liu³

et al. 2019

Plasma Phys. Control. Fusion

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The influence of high-Z dopant (Bromine) in low-Z foam (polystyrene) target on laser-driven fast electron propagation is studied by the 3D hybrid particlein-cell (PIC)/fluid code HEETS. It is found that the fast electrons are better confined in doped targets due to the increasing resistivity of the target, which induces a stronger resistive magnetic field which acts to collimate the fast electron propagation. The energy deposition of fast electrons into the background target is increased slightly in the doped target, which is beneficial for applications requiring long distance propagation of fast electrons, such as fast ignition.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Control of fast electron propagation in foam target by high-Z doping

Xu¹,

Yang²,

Liu³

et al. 2019

Plasma Phys. Control. Fusion

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show abstract

“…The collimation criterion with such a magnetic field structure has not been considered and is not understood yet. In recent years, there has been significant interest in collimating fast electrons by use of high magnetic fields [40][41][42][43]. The magnetic fields can be as high as 1 kT when nanosecond driving lasers with energy at the kJ level are applied [42,44].…”

Section: Nuclear Fusionmentioning

confidence: 99%

Collimation of high-current fast electrons in dense plasmas with a tightly focused precursor intense laser pulse

Yang

Sheng

et al. 2019

Nucl. Fusion

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High current fast electrons at the megaampere level provide a unique way to generate high energy density states of matter, which are related to many applications. However, the large divergence angle of the fast electrons typically over 50 degrees is a significant disadvantage for applications. The guiding effect by the self-generated azimuthal magnetic fields of the fast electron current is found to be very limited due to their cone-shaped spatial structure. In this work, we present a new understanding on the collimation conditions of fast electrons under such a magnetic field structure. It is shown that the transverse peak position of the magnetic field layer plays a crucial role to collimate the fast electrons rather than its magnitude. Based upon this, a new two-pulse collimating scheme is proposed, where a guiding precursor pulse is adopted to form proper azimuthal magnetic fields and a main pulse is for fast electron generation as usual. The present scheme can be implemented relatively easily with the precursor lasers at the 10 TW level with a duration of two hundred femtoseconds, with which the divergence angle of fast electrons driven by the main pulse can be confined within a few degrees. Our scheme can find practical applications in high energy density science.

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“…The transport of relativistic electrons can be inhibited by charge separation fields until a cold return current is generated or the electrons from ionization neutralize space charge fields. The transport of relativistic electrons through targets was found to be dependent on target materials, showing spatial disruption in insulators but more uniform propagation in metals [8][9][10] . A collimated ionization channel [11] or an ionization front behind the collimated jet [12] was observed by optical shadowgraph during ultraintense laser interactions with silica targets with propagation velocities (0.4c-0.5c) much slower than the speed of light.…”

Section: Introductionmentioning

confidence: 99%

Transport of ultraintense laser-driven relativistic electrons in dielectric targets

Yang

Ren

et al. 2020

High Pow Laser Sci Eng

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Ultraintense laser-driven relativistic electrons provide a way of heating matter to high energy density states related to many applications. However, the transport of relativistic electrons in solid targets has not been understood well yet, especially in dielectric targets. We present the first detailed two-dimensional particle-in-cell simulations of relativistic electron transport in a silicon target by including the field ionization and collisional ionization processes. An ionization wave is found propagating in the insulator, with a velocity dependent on laser intensity and slower than the relativistic electron velocity. Widely spread electric fields in front of the sheath fields are observed due to the collective effect of free electrons and ions. The electric fields are much weaker than the threshold electric field of field ionization. Two-stream instability behind the ionization front arises for the cases with laser intensity greater than $5\times 10^{19}~\text{W}/\text{cm}^{2}$ that produce high relativistic electron current densities.

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Energy deposition of fast electrons in dense magnetized plasmas

Cited by 5 publications

References 39 publications

Control of fast electron propagation in foam target by high-Z doping

Control of fast electron propagation in foam target by high-Z doping

Collimation of high-current fast electrons in dense plasmas with a tightly focused precursor intense laser pulse

Transport of ultraintense laser-driven relativistic electrons in dielectric targets

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