Generation of very low energy-spread electron beams using low-intensity laser pulses in a low-density plasma

Upadhyay, Ajay K.; Samant, Sushil Arun; Sarkar, D.; Jha, Pallavi; Krishnagopal, S.

doi:10.1063/1.3569825

Cited by 4 publications

(3 citation statements)

References 38 publications

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“…It has been suggested, and also observed that operating the wakefield accelerator at the threshold plasma density is advantageous, as it leads to comparatively higher stability (i.e. minimal fluctuation of electron beam parameters) and narrowenergy spread with low or almost zero background [9,80,81]. Here in the present experiment we show the effect of threshold plasma density on electron beam quality in a DLA dominated regime.…”

Section: Introductionsupporting

confidence: 58%

Direct laser acceleration of electrons in a high-Z gas target and the effect of threshold plasma density on electron beam generation

Hazra

Moorti

Mishra

et al. 2019

Plasma Phys. Control. Fusion

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An experimental study of laser driven electron acceleration in N 2 and N 2 -He mixed gas-jet target using laser pulses of duration ~60-70 fs is presented. Generation of relativistic electron beam with quasi-thermal spectra was observed at a threshold density of ~1.6×10 18 cm -3 in case of pure N 2 , and the threshold density was found to increase with increasing doping concentration of He.At an optimum fraction of 50% of He in N 2, generation of quasi-monoenergetic electron beams was observed at a comparatively higher threshold density of ~2×10 18 cm -3 , with an average peak energy of ~168 MeV, average energy spread of ~21%, and average total beam charge of ~220 pC. Electron acceleration could be attributed to the direct laser acceleration as well as the hybrid mechanism. Observation of an optimum fraction of He in N 2 (in turn threshold plasma density) for comparatively better quality electron beam generation could be understood in terms of the plasma density dependent variation in the dephasing rate of electrons with respect to transverse oscillating laser field. Results are also supported by the 2D PIC simulations performed using code EPOCH.

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Section: Introductionsupporting

confidence: 58%

Direct laser acceleration of electrons in a high-Z gas target and the effect of threshold plasma density on electron beam generation

Hazra

Moorti

Mishra

et al. 2019

Plasma Phys. Control. Fusion

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“…Theory and simulations suggest that controlling the evolution of the driving laser pulse can improve localization of electron injection, leading to the near elimination of the low-energy background [31,33,41,42]. Alternatively, matching the pulse for self-guiding (in a uniform plasma) and working close to the self-injection threshold can reduce backgrounds significantly [28,43]. Realization of this approach in the laboratory, however, appears to require very demanding laser pulse and target quality.…”

Section: Introductionmentioning

confidence: 99%

Stable, tunable, quasimonoenergetic electron beams produced in a laser wakefield near the threshold for self-injection

Banerjee

Kalmykov

Powers

et al. 2013

Phys. Rev. ST Accel. Beams

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Stable operation of a laser-plasma accelerator near the threshold for electron self-injection in the blowout regime has been demonstrated with 25-60 TW, 30 fs laser pulses focused into a 3-4 millimeter length gas jet. Nearly Gaussian shape and high nanosecond contrast of the focused pulse appear to be critically important for controllable, tunable generation of 250-430 MeV electron bunches with a lowenergy spread, $10 pC charge, a few-mrad divergence and pointing stability, and a vanishingly small low-energy background. The physical nature of the near-threshold behavior is examined using threedimensional particle-in-cell simulations. Simulations indicate that properly locating the nonlinear focus of the laser pulse within the plasma suppresses continuous injection, thus reducing the low-energy tail of the electron beam.

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“…The same guiding can also be achieved by choosing a spot-size comparable to or slightly larger than the plasma wavelength, but with an intensity that is less than in the matched case (so that power is nearly the same). 6,8,[18][19][20] The generation of GeV-class beams, both in experiments 6,7,[9][10][11] and in simulations, 13,[19][20][21][22][23][24] has been observed in such plasmas of lower density.…”

Section: Introductionmentioning

confidence: 97%

Tailoring the laser pulse shape to improve the quality of the self-injected electron beam in laser wakefield acceleration

2013

Self Cite

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In laser wakefield acceleration, tailoring the shape of the laser pulse is one way of influencing the laser-plasma interaction and, therefore, of improving the quality of the self-injected electron beam in the bubble regime. Using three-dimensional particle-in-cell simulations, the evolution dynamics of the laser pulse and the quality of the self-injected beam, for a Gaussian pulse, a positive skew pulse (i.e., one with sharp rise and slow fall), and a negative skew pulse (i.e., one with a slow rise and sharp fall) are studied. It is observed that with a negative skew laser pulse there is a substantial improvement in the emittance (by around a factor of two), and a modest improvement in the energy-spread, compared to Gaussian as well as positive skew pulses. However, the injected charge is less in the negative skew pulse compared to the other two. It is also found that there is an optimal propagation distance that gives the best beam quality; beyond this distance, though the energy increases, the beam quality deteriorates, but this deterioration is least for the negative skew pulse. Thus, the negative skew pulse gives an improvement in terms of beam quality (emittance and energy spread) over what one can get with a Gaussian or positive skew pulse. In part, this is because of the lesser injected charge, and the strong suppression of continuous injection for the negative skew pulse. V C 2013 American Institute of Physics. [http://dx.

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Generation of very low energy-spread electron beams using low-intensity laser pulses in a low-density plasma

Cited by 4 publications

References 38 publications

Direct laser acceleration of electrons in a high-Z gas target and the effect of threshold plasma density on electron beam generation

Direct laser acceleration of electrons in a high-Z gas target and the effect of threshold plasma density on electron beam generation

Stable, tunable, quasimonoenergetic electron beams produced in a laser wakefield near the threshold for self-injection

Tailoring the laser pulse shape to improve the quality of the self-injected electron beam in laser wakefield acceleration

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