The dependency of the stochastic heating to the pulse shape in intense laser-plasma interaction

Khalilzadeh, Elnaz; Chakhmachi, Amir; Yazdanpanah, J.

doi:10.1016/j.ijleo.2020.165249

Cited by 6 publications

(3 citation statements)

References 35 publications

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“…In the following, as seen in Figure 7, the treatment of the electric field and the phase space curves are different by employing the field-ionized and the pre-plasma conditions. The results of the previous research studies [17,18] show that for the pulses with smooth rise-time, the backscattered Raman radiations are generated in the early times of interaction. In this case, if the amplitude of these Raman backscattering radiations meets the Mendonca threshold limit a 1 a 2 = 1∕16, the chaos occurs.…”

Section: F I G U R E 10mentioning

confidence: 89%

“…The last mechanism is related to the stochastic acceleration of the electrons in the presence of two counter-propagating laser fields. [11][12][13][14][15][16][17][18] It was found earlier from particle-in-cell (PIC) simulations that through this scheme, energetic electrons can be generated higher than the ponderomotive potential of the first laser pulse. [13,14] In another work, it was shown that in sufficiently long laser pulses, the backward Raman-scattered radiation can act as a second electromagnetic radiation.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, energetic electrons are produced through the stochastic mechanism [15] in interaction of the intense laser pulse with under-dense plasma. Khalilzadeh et al [16][17][18] revealed that the plasma behaviour, the pulse evolution, and the acceleration mechanisms are strongly dependent on the pulse shape, so, for pulses with different rise-times, there are different acceleration mechanisms to energize electrons. In this work, it was indicated that in the interaction of the smooth rising laser pulses with the plasma, because of the long length of the pulse rise-time duration, a strong ponderomotive force cannot be produced and parametric instabilities such as Raman backward scattering can grow from a noise level and reach to a specified level.…”

Section: Introductionmentioning

confidence: 99%

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Electron energy spectrum in the field‐ionized plasma

Khalilzadeh

Chakhmachi

Dehghani

et al. 2021

Contributions to Plasma Physics

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In this article, the effect of ionization on the energy spectrum of electrons within the interaction of a laser pulse with hydrogen atoms is investigated using particle-in-cell simulation codes. The results show that the behaviour of electrons' energy distribution function in the field-ionized plasma, which occurred due to the field ionization, compared with that in the pre-plasma strongly depends on the pulse shape. For short rise-time pulses (here 30 fs), due to the rapid enhancement of laser electric field, ionization occurs quickly, and as a result, there is not much difference in the electron energy in both the media.However, for pulses with rise time of 40 fs, in the pre-plasma state, the electron population reaches higher energies compared with the field-ionized plasma state. The main reason for this difference is the nonlinear wave breaking that happens earlier due to density inhomogeneity in the field-ionized plasma. On the other hand, at longer rise-time pulses (here 60 and 70 fs), electrons achieve higher energies in the field-ionized plasma than those in the case of pre-plasma.In this case, because of density fluctuations in the field-ionized plasma, the Raman backscattered radiations are seeded by a strong initial noise at the earlier times and the Mendonca condition for chaos threshold is met sooner. Therefore, the electrons gain more energy through the stochastic mechanism that is in agreement with chaotic nature of the motion.

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Section: F I G U R E 10mentioning

confidence: 89%