ترغب بنشر مسار تعليمي؟ اضغط هنا

Two stage $gamma$ ray emission via an ultrahigh intensity laser pulse interaction with a laser-wakefield accelerated electron beam

258   0   0.0 ( 0 )
 نشر من قبل Mamat Ali Bake
 تاريخ النشر 2019
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

We investigate the generation of twin $gamma$ ray beams in collision of an ultrahigh intensity laser pulse with a laser wakefield accelerated electron beam by using particle-in-cell simulation. We consider the composed target of a homogeneous underdense preplasma in front of an ultrathin solid foil. The electrons in the preplasma are trapped and accelerated by the wakefield. When the laser pulse is reflected by the thin solid foil, the wakefield accelerated electrons continue to move forward and passing through the foil almost without the influence of the reflected laser pulse and the foil. Consequently, two groups of $gamma$ ray flashes, with tunable time delay and energy, are generated by the wakefield accelerated electron beam interacting with the reflected laser pulse from the foil as well as another counter propagating petawatt laser pulse in the behind the foil. The dependence of the $gamma$ photon emission on the preplasma densities, driving laser polarization and the foil are studied.



قيم البحث

اقرأ أيضاً

The dynamics of energetic particles in strong electromagnetic fields can be heavily influenced by the energy loss arising from the emission of radiation during acceleration, known as radiation reaction. When interacting with a high-energy electron be am, todays lasers are sufficiently intense to explore the transition between the classical and quantum radiation reaction regimes. We report on the observation of radiation reaction in the collision of an ultra-relativistic electron beam generated by laser wakefield acceleration ($varepsilon > 500$ MeV) with an intense laser pulse ($a_0 > 10$). We measure an energy loss in the post-collision electron spectrum that is correlated with the detected signal of hard photons ($gamma$-rays), consistent with a quantum (stochastic) description of radiation reaction. The generated $gamma$-rays have the highest energies yet reported from an all-optical inverse Compton scattering scheme, with critical energy $varepsilon_{rm crit} > $ 30 MeV.
High-flux polarized particle beams are of critical importance for the investigation of spin-dependent processes, such as in searches of physics beyond the Standard Model, as well as for scrutinizing the structure of solids and surfaces in material sc ience. Here we demonstrate that kiloampere polarized electron beams can be produced via laser-wakefield acceleration from a gas target. A simple theoretical model for determining the electron beam polarization is presented and supported with self-consistent three-dimensional particle-in-cell simulations that incorporate the spin dynamics. By appropriately choosing the laser and gas parameters, we show that the depolarization of electrons induced by the laser-wakefield-acceleration process can be as low as 10%. Compared to currently available sources of polarized electron beams, the flux is increased by four orders of magnitude.
Spin-polarization of an ultrarelativistic electron beam head-on colliding with an ultraintense laser pulse is investigated in the quantum radiation-reaction regime. We develop a Monte-Carlo method to model electron radiative spin effects in arbitrary electromagnetic fields by employing spin-resolved radiation probabilities in the local constant field approximation. Due to spin-dependent radiation reaction, the applied elliptically polarized laser pulse polarizes the initially unpolarized electron beam and splits it along the propagation direction into two oppositely transversely polarized parts with a splitting angle of about tens of milliradians. Thus, a dense electron beam with above 70% polarization can be generated in tens of femtoseconds. The proposed method demonstrates a way for relativistic electron beam polarization with currently achievable laser facilities.
Particle energy chirp is shown to be a useful instrument in the staging laser wake field acceleration directed to generation of high-quality dense electron beams. The chirp is a necessary tool to compensate non-uniformity of acceleration field in lon gitudinal direction and achieve essential reduction of energy dispersion. This is demonstrated via particle-in-cell simulations exploiting the splitting technique for plasma and beam electrons. Properly chosen beam chirps allow decrease in the energy dispersion of order of magnitude in every single stage during acceleration to the GeV energy range.
121 - R. J. Garland , K. Poder , J. Cole 2014
Laser-wakefield acceleration is a promising technique for the next generation of ultra-compact, high-energy particle accelerators. However, for a meaningful use of laser-driven particle beams it is necessary that they present a high degree of pointin g stability in order to be injected into transport lines and further acceleration stages. Here we show a comprehensive experimental study of the main factors limiting the pointing stability of laser-wakefield accelerated electron beams. It is shown that gas-cells provide a much more stable electron generation axis, if compared to gas-jet targets, virtually regardless of the gas density used. A sub-mrad shot-to-shot fluctuation in pointing is measured and a consistent non-zero offset of the electron axis in respect to the laser propagation axis is found to be solely related to a residual angular dispersion introduced by the laser compression system and can be used as a precise diagnostic tool for compression oprtimisation in chirped pulse amplified lasers.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا