Intense electron beam propagation through insulators: Ionization front structure and stability

Krasheninnikov, S. I.; Kim, A. V.; Frolov, B. K.; Stephens, R. B.

doi:10.1063/1.1978407

Cited by 34 publications

(45 citation statements)

References 19 publications

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“…As seen in Eq. (21), the multiple scattering can slightly reduce the total radiation. The correction term to the ideal Cerenkov radiation is the order of ðq=xÞ.…”

Section: Radiation From Energetic Electrons With Inclusion Of Mulmentioning

confidence: 98%

“…The beam velocity defined by the ionization front is smaller than electron velocity and can be comparable or even smaller than the light speed in the medium. 21,22 Cerenkov radiation is supposed to be emitted from those energetic electrons in front of the beam head. However, as an electron moves in a medium, it suffers multiple scattering with the nuclei in medium, and no longer moves uniformly.…”

Section: Introductionmentioning

confidence: 99%

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Effect of multiple scattering on Cerenkov radiation from energetic electrons

Zheng

2013

Physics of Plasmas

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Cerenkov radiation can be used as a diagnostic tool to study energetic electrons generated in ultra-intense laser matter interactions. However, electrons suffer scattering with nuclei as they move in a medium. In this article, we theoretically study the effect of multiple scattering on Cerenkov radiation, and obtain analytical formulas under some circumstances. The results show that when the speed of an energetic electron is not close to the light speed in the medium, Cerenkov radiation is just slightly decreased due to multiple scattering. In the case that the electron speed is very close to the light speed in the medium, the effect of multiple scattering becomes significant, and the radiation is dominated by bremsstrahlung. V C 2013 American Institute of Physics. [http://dx.

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“…As seen in Eq. (21), the multiple scattering can slightly reduce the total radiation. The correction term to the ideal Cerenkov radiation is the order of ðq=xÞ.…”

Section: Radiation From Energetic Electrons With Inclusion Of Mulmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Effect of multiple scattering on Cerenkov radiation from energetic electrons

Zheng

2013

Physics of Plasmas

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“…There exists several explanations of electron transport through metals and insulators. 26,27 Particularly, Krasheninnikov et al 27 have discussed in detail the growth of electron beam instabilities in insulator targets. One likely explanation for large differences in peak and bulk temperatures arises in the differences in nuclear charge between Al and CH samples.…”

Section: Hot Layer Temperaturementioning

confidence: 99%

Creation of hot dense matter in short-pulse laser-plasma interaction with tamped titanium foils

et al. 2007

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Dense titanium plasma has been heated to an electron temperature up to 1300 eV with a 100 TW, high intensity short-pulse laser. The experiments were conducted using Ti foils ͑5 m thick͒ sandwiched between layers of either aluminum ͑1or2 m thick͒ or plastic ͑2 m thick͒ to prevent the effects of prepulse. Targets of two different sizes, i.e., 250ϫ 250 m 2 and 1 ϫ 1m m 2 were used. Spectral measurements of the Ti inner-shell emission, in the region between 4 and 5 keV, were taken from the front-side ͑i.e., the laser illuminated side͒ of the target. The data show large shifts in the K␣ emission from open-shell ions, suggesting bulk heating of the sample at near solid density, which was largest for reduced mass targets. Comparison with collisional radiative and 2D radiation hydrodynamics codes indicates a peak temperature of T e,peak = 1300 eV of solid titanium plasma in ϳ0.2 m thin layer. Higher bulk temperature ͑T e,bulk = 100 eV͒ for aluminum tamped compared to CH tamped targets ͑T e,bulk =40 eV͒ was observed. A possible explanation for this difference is described whereby scattering due to the nuclear charge of the tamping material leads to modified electron transport behavior.

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“…Propagation of the electron beam through fully ionized plasmas has been studied for several decades [3]. However, relatively few studies investigating the ionization dynamics of neutral materials have been reported [4][5][6][7][8].A high current density electron beam propagated through a neutral material can generate a large electrostatic field owing to the effect of charge nonneutrality. The large electrostatic field can directly ionize the neutral material, a process referred to as field ionization [9].…”

mentioning

confidence: 99%

mentioning

confidence: 99%

Role of Field and Electron Impact Ionization in Ionization Front Generated by an Intense Electron Beam

Katō

Kishimoto

Takahashi

et al. 2012

Plasma and Fusion Research

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The interaction of an intense electron beam with a neutral background material is studied. The neutral material is ionized by the electrostatic field generated by the intense electron beam and electron impact ionization. The structure of the ionization front is analyzed using a one-dimensional model. The structure is determined primarily by electron impact ionization of the ionized background electrons. In addition, the field ionization contributes to the generation of the ionization front by increasing the density of the electron beam. An intense electron beam can be efficiently generated by intense short laser pulses. One particular application for this is energetic ion sources using thin foils [1,2]. In this regard, the understanding of the dynamics of the electron beam is crucial. Propagation of the electron beam through fully ionized plasmas has been studied for several decades [3]. However, relatively few studies investigating the ionization dynamics of neutral materials have been reported [4][5][6][7][8].A high current density electron beam propagated through a neutral material can generate a large electrostatic field owing to the effect of charge nonneutrality. The large electrostatic field can directly ionize the neutral material, a process referred to as field ionization [9]. Furthermore, the field enhances impact ionization by the background electrons. However, once a plasma is created, it strongly screens the electrostatic field. The ionization processes and electrostatic field screening significantly affect the properties of the plasma.In this paper, the structure of the ionization front in the direction of the initial electron beam propagation is studied using a one-dimensional stationary model, and the role of the ionization processes is clarified. We assumed that the electron motion is separated by the components of the ionized background and input high-energy beam electrons. The density of the background electrons is usually much higher than that of the high-energy electron beam. We assumed that the background electron motion is described by electron fluid equations and that the atom only changes the charge states. The density profile of an electron beam does not change, and its energy b is constant; that is, the author's e-mail: s.kato@aist.go.jp beam only propagates under the same initial density n b and velocity u b . Thus, the evolution of the density of a background electron n e and that of an ion n i are described bywhere N and ν I are density and ionization rate of the atom, respectively, and u d is the electron fluid velocity, which is determined by u d = −eE/m e ν e , where E is the electrostatic field, e and m e are the electron charge and mass, respectively, and ν e is the electron collision frequency of a background electron. The electron collision frequency and ionization rate are dependent on the type of material and the density and strength of the electric field. In this model, the ionization rate ν I is assumed to consist of contributions from the electric field and electron impa...

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Intense electron beam propagation through insulators: Ionization front structure and stability

Cited by 34 publications

References 19 publications

Effect of multiple scattering on Cerenkov radiation from energetic electrons

Effect of multiple scattering on Cerenkov radiation from energetic electrons

Creation of hot dense matter in short-pulse laser-plasma interaction with tamped titanium foils

Role of Field and Electron Impact Ionization in Ionization Front Generated by an Intense Electron Beam

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