Positron acceleration in a hollow plasma channel up to TeV regime

Abstract

Nowadays, human's understanding of the fundamental physics is somehow limited by the energy that our high energy accelerators can afford. Up to 4 TeV protons are realized in the Large Hadron Collider (LHC). Leptons, such as electrons and positrons, however gained energies of about 100 GeV or less. Multi-TeV lepton accelerators are still lacking due to the relatively low acceleration gradient of conventional methods, which may induce unbearable cost. On the other hand, plasmas have shown extraordinary potential in accelerating electrons and ions, providing orders of magnitude higher acceleration fields of 10–100 GV/m. In such context, we propose a plasma-based high-energy lepton accelerator, in which a weakly focusing plasma structure is formed near the beam axis. The structure preserves the emittance of the accelerated beam and produces low radiation losses. Moreover, the structure allows for a considerable decrease of the witness energy spread at the driver depletion stage.

Transverse electron-scale instability in relativistic shear flows

“…The MI was also shown to be robust against a variety of nonideal (realistic) shear conditions: (i) operating under relativistic thermal effects, (ii) different densities between shearing flows, (iii) smooth velocity shear profiles (L v ω pe /c 1), and, quite surprisingly, (iv) even in the absence of contact between flows (L g ω pe /c ≫ 1 for highly relativistic shears). Relativistic collisionless sheared flow conditions, capable of triggering the MI, may be reproduced in the laboratory by propagating a globally neutral relativistic e − e + beam [38] in a hollow plasma or dielectric channel [39,40], allowing experimental access to the MI and sheared flow dynamics on the electron scale. We have begun to explore this configuration in [41].…”

“…The exponential growth associated with the linear development of the instability is observed for 10 tω pe 30, matching the theoretical growth rate. The instability saturates at tω pe 40, approximately when the size of the mushroomlike density structure is on the order of 2π/k seed [ Fig. 2(a3)].…”

Multi-proton bunch driven hollow plasma wakefield acceleration in the nonlinear regime

“…In particular, an advantageous nonlinear regime was discovered for short proton bunches of a high charge [6][7][8] . However, these bunches are difficult to produce.…”

“…Nevertheless, the obtainable energy gain of the witness bunch in one acceleration stage is subject to the transformer ratio limit 2 and thereby cannot significantly exceed the energy of driver particles. Under this circumstance, proton driven PWFA [3][4][5][6][7][8] (PD-PWFA) looks particularly competitive as existing proton bunches have huge energy and large populations. For instance, the nominal bunches in the Large Hadron Collider (LHC) are of 6.5 TeV in energy and of 1.15×10 11 protons in bunch population, which corresponds to 125 kJ/bunch.…”

“…Up to now, all theoretical studies of hollow channels were dedicated to short drivers (both for particle beams [6][7][8][51][52][53][54] and for lasers 40,[55][56][57][58][59][60][61][62] ). In particular, an advantageous nonlinear regime was discovered for short proton bunches of a high charge [6][7][8] .…”