Generation of polarized particle beams at relativistic laser intensities

Abstract

The acceleration of polarized electrons, positrons, protons and ions in strong laser and plasma fields is a very attractive option for obtaining polarized beams in the multi-mega-electron volt range. Recently, there has been substantial progress in the understanding of the dominant mechanisms leading to high degrees of polarization, in the numerical modeling of these processes and in their experimental implementation. This review paper presents an overview on the current state of the field, and on the concepts of polarized laser–plasma accelerators and of beam polarimetry.

Polarized proton acceleration in ultraintense laser interaction with near-critical-density plasmas

“…( 1), q mc (a p + 1 γ )B = 2.67×10 13 Hz, where the cycle of rotation is nearly 23 fs, implying that the polarization of the proton beam could also be affected by the laser field directly. This means that the spin of the proton should also be considered, although there are many works focusing on the spin motion of electrons (or positrons) in ultraintense laser fields [9,33,34].…”

“…In order to effectively utilize and develop laser plasma acceleration, many characteristics of particle beams, e.g., energy spread, charge, pulse duration, and emittance, have been steadily improved. However, the polarization of particles has rarely been studied in plasma-based acceleration [9].…”

Acceleration of spin-polarized proton beams via two parallel laser pulses

“…In recent years, laser-plasma based acceleration schemes of spin-polarized particle beams have gained a lot of interest due to the compactness of the needed setups. This has brought forward the numerical investigation of several acceleration schemes (see [3] for a general overview). A first experimental study on the acceleration of such polarized beams has recently been carried out at Phelix (GSI Darmstadt) using a hyperpolarized 3 He gas jet target.…”

“…This has brought forward the numerical investigation of several acceleration schemes (see [3] for a general overview). A first experimental study on the acceleration of such polarized beams has recently been carried out at Phelix (GSI Darmstadt) using a hyperpolarized 3 He gas jet target. The data from this measurement are still being analyzed [4].…”

“…For protons the options become more sparse: while several schemes usable for the efficient acceleration of proton beams are known, only a few of them allow for the target's pre-polarization. Setups like target normal sheath acceleration would require pre-polarized cryogenic * lars.reichwein@hhu.de hydrogen foils which are experimentally extremely challenging [3]. The same problem arises in the case of multilayer targets [8].…”