Conveners
WG6: Ion acceleration and developments towards fusion
- Marco Borghesi (Queen's University Belfast)
- Matt Zepf (Helmholtz Institut Jena)
WG6: Ion acceleration and developments towards fusion
- Marco Borghesi (Queen's University Belfast)
- Matt Zepf (Helmholtz Institut Jena)
Despite the huge potential of laser-driven proton acceleration to provide compact sources of MeV proton beams suitable for a variety of applications, several factors hamper their wider adoption including: the challenges associated with operating these accelerators at high-repetition rate; low shot-to-shot stability; and large beam divergence which leads to rapidly decreasing proton flux with...
The interaction between relativistic intensity laser pulses and near-critical density targets has been sought after to increase the efficiency of laser-plasma energy coupling, particularly for proton
acceleration. To achieve this density regime for high repetition rate applications, one approach is to use gas targets, provided that stringent target density profile requirements are met,...
Many applications require a (quasi) continuous source of ions and neutrons operating in a 24/7 mode. Recent developments of few-cycle laser systems with an average optical power of 100 W have laid the technological basis for the development of such a particle source.
In the experimental series in ELI-ALPS, Hungary, first we have demonstrated that ions can be efficiently accelerated above 1MeV...
We report on experimental observation on periodic modulation in the energy spectrum of laser accelerated proton beams. Interestingly, theoretical model and two-dimensional particle-in-cell simulations, in good agreement with the experimental finding, indicated that such modulation is associated with periodic modulated electron density induced by transverse instability. These results, may have...
We present the preliminary results of proton acceleration from tens of nanometer thick plastic foils that are irradiated by a $10^{21}$ W/cm$^2$ laser pulse with 25 fs pulse duration and 1.8 $\mu$m focal spot size (FWHM). We consider the effect of circular (CP) and linear (LP) polarization on the proton energy spectra. For CP we observe an optimum in the proton energy in dependence of the...
We present our recent findings on laser efficient laser ion acceleration with various target systems.
One target system is based on a Paul-trap, which allows us to position sub-focus sized spherical targets (1 µm diameter) with sub-micrometer precision into the focus.
The other target system are thin plastic foils(with 10 - 200 nm thickness).
Experiments were conducted at the JeTi laser...
The ALBUS technology platform tackles the challenges arising from the unique properties of laser-driven ion beams. The central part of ALBUS is the advanced pulsed electromagnet technology adapted from high-field laboratory know-how in combination with custom-designed current pulse generators, with a repetition rate matching the pulsed nature of a common LPA source, aiming towards 1 Hz.
The...
The use of polarized $^3$He ions in storage rings opens a new window to investigate nuclear forces, because nuclear polarized $^3$He ions can be regarded as an ideal substitute for polarized neutron beams. Polarized $^3$He$^{2+}$ ions were used in the 1960’s, but either the nuclear polarization or the intensity of the ion sources was rather small. Numerous efforts to improve the performance of...
In laser-driven particle acceleration the choice of the target material can have a large impact on the acceleration process. Therefore, a laser-driven proton acceleration experiment was conducted at the POLARIS laser system, where liquid micro-droplets made of water or ethylene glycole were used as targets.
Droplet chains were created by a pressurized capillary nozzle, which was made to...
We discuss relativistic laser interaction with overdense plasmas, where the laser pulse is incident parallel to the plasma surface, the so-called “peeler” regime [1]. The laser pulse impinges on an edge of a tape. The edge allows for an efficient conversion of the laser pulse into a surface plasma wave (SPW). The SPW peels off and accelerates electrons (tens of nC) from the target skin layer....
Acceleration of proton beams in laser-driven plasma waves is challenging, owing to the difficulty of trapping the slow velocity protons in the relativistic plasma wave. In a laser-plasma accelerator, the phase velocity of the plasma wave is approximately the group velocity of the laser driver propagating in the underdense plasma. Due to their high rest mass, protons only reach comparable...
Laser-driven proton acceleration can provide ultra-short, high-charge, low-emittance bunches. Despite extensive research, current laser-ion sources fall short of delivering the desired energies for pivotal applications, like proton tumor therapy. Moreover, the generated non-relativistic beams cannot be injected into high-$\beta$ accelerator elements for further acceleration and use in...
