Self-Organizing GeV, Nanocoulomb, Collimated Proton Beam from Laser Foil Interaction at7×1021  W/cm2

Abstract

We report on a self-organizing, quasistable regime of laser proton acceleration, producing 1 GeV nanocoulomb proton bunches from laser foil interaction at an intensity of 7 x 10;{21} W/cm;{2}. The results are obtained from 2D particle-in-cell simulations, using a circular polarized laser pulse with Gaussian transverse profile, normally incident on a planar, 500 nm thick hydrogen foil. While foil plasma driven in the wings of the driving pulse is dispersed, a stable central clump with 1-2lambda diameter is forming on the axis. The stabilization is related to laser light having passed the transparent parts of the foil in the wing region and enfolding the central clump that is still opaque. Varying laser parameters, it is shown that the results are stable within certain margins and can be obtained both for protons and heavier ions such as He;{2+}.

Dynamic study of a compressed electron layer during the hole-boring stage in a sharp-front laser interaction region

“…5(a), the foil thickness l 0 ¼ 0:5 is obtained based on Eqs. (2)- (5), (17), and (18), consistent with the theoretical results in Ref. [23].…”

“…High-energy ions accelerated by such intense laser interacting with the solid target can be prospectively applied in fast ignition for inertial confinement fusion [3,4], medical therapy [5,6], and proton imaging [7], among others. Radiation pressure acceleration (RPA) using circularly polarized (CP) laser pulses provides a promising way to obtain a high-energy ion beam with monoenergetic spectrum in a much more efficient manner, compared with target normal sheath acceleration [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Yan et al [12] proposed the phase-stable-acceleration (PSA) mechanism in the RPA regime [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] to synchronously accelerate and bunch ions within skin depth of the laser pulse to get a monoenergetic ion beam in the longitudinal direction.…”

Laser-driven collimated tens-GeV monoenergetic protons from mass-limited target plus preformed channel

“…[11][12][13] Existing studies have shown that GeV proton beams can be obtained by RPA using circularly polarized (CP) lasers with intensity above 10 22 W/cm 2 . [14][15][16] However, because of transverse instabilities and hole-boring by the laser pulse, [14][15][16][17] the acceleration length is rather limited and it is difficult to enhance proton energy without still higher laser intensity. Recently, it has been shown that tens GeV proton beams 18,19 can be obtained by sequential radiation pressure and bubble acceleration or a moving double-layer, or in a two-phase acceleration regime 20,21 by ultra-relativistic lasers.…”

Efficient acceleration of monoenergetic proton beam by sharp front laser pulse

“…27,36,37 We investigate why and how the steepness a 0 / t up of the laser front plays a critical role in addition to the laser intensity, the plasma density, and the foil thickness. Here a 0 = eE L / m e L c is the normalized amplitude, m e and e are the electron mass and charge, respectively, E L is the laser electric field, L is the laser frequency, c is the light speed, and t up is the rising time of the laser pulse.…”