Laser plasma accelerator driven by a super-Gaussian pulse

Abstract

A laser wakefield accelerator (LWFA) with a weak focusing force is considered to seek improved beam quality in LWFA. We employ super-Gaussian laser pulses to generate the wakefield and study the behavior of the electron beam dynamics and synchrotron radiation arising from the transverse betatron oscillations through analysis and computation. We note that the super-Gaussian wakefields radically reduce the betatron oscillations and make the electron orbits mainly ballistic over a single stage. This feature permits to obtain small emittance and thus high luminosity, while still benefitting from the low-density operation of LWFA (Nakajima et al. 2011 Phys. Rev. ST Accel. Beams14, 091301), such as the reduced radiation loss, less number of stages, less beam instabilities, and less required wall plug power than in higher density regimes.

Self-focusing and defocusing phenomena of super-Gaussian laser beams in plasmas carrying density gradient

“…Owing to their larger penetration or propagation in plasma, the super-Gaussian beams are expected to generate nonlinear current in larger region of the plasma and hence, the excitation of THz radiation with very significant and tunable field. This property of these beams will also enhance the interaction length of charged particles with the wakefield [45] excited in a plasma for the particle acceleration [7,46,47]. On the other hand, a little deviation in the super-Gaussian beam profiles with a small dip in the middle of their peak intensity region (generally termed as cosh-Gaussian laser beams) have been used for the second harmonic generation in cold quantum plasma [48] and in ordinary plasma with the relativistic-ponderomotive nonlinearities in the medium [49] due to their better focusing.…”

Fundamental Physics Explored With High Intensity Laser

“…Tajima et al [23] have suggested to accelerate electrons toward PeV by LWFA, utilizing a MJ laser (such as the LMJ laser [48]). The conventional RF acceleration may have a difficulty to reach PeV energies, as the synchrotron radiation power loss begins to become formidable beyond 30 TeV [49].…”

Strong Terahertz radiation generation via wakefield in collisional plasma

“…The researchers all over the world are putting their efforts to generate the THz radiation sources where the laser plasma interaction has vital role to play. There are a lot of studies on laser plasma interaction, which talk about different mechanisms [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. Extremely powerful THz radiations have been achieved by interaction of chirped [24], few cycle laser pulses [25] and tailored laser pulses [26] with plasmas.…”

“…Extremely powerful THz radiations have been achieved by interaction of chirped [24], few cycle laser pulses [25] and tailored laser pulses [26] with plasmas. In this regard, Villa et al [27] have been able to shape and characterize laser pulses for high gradient accelerators and Ostermayr et al [28] and Malik and co-workers [31,32] have employed super-Gaussian (sG) pulse for laser plasma interaction with regard to their self-focusing effect. We have also made theoretical investigations for the efficient use of super-Gaussian lasers for obtaining THz radiation based on laser beat process [29,34].…”