25 / 2023-03-31 12:19:00

Generation of energetic proton beam by expanding micro-nozzle acceleration (EMNA)

Proton Acceleration,3D PIC Simulation,Micro-Nozzle

极端光下的基础物理学 > 粒子加速-海报

We propose a novel ion acceleration scheme, Expanding Micro-Nozzle Acceleration

(EMNA), to generate proton beams with low divergence and substantially higher ion

kinetic energies than with conventional schemes. The performance of EMNA is

studied with 3D-PIC (Particle-in-Cell) simulations. EMNA target is composed of a

micron-sized hydrogen bullet and a micro-nozzle made of middle-high Z materials,

which is placed on the downwind side of the hydrogen bullet. Under the illumination

of ultra-intense laser with intensities at 10 20 - 10 22 W/cm 2 , the protons are accelerated

by the twofold electrostatic forces, i.e., (1) the electric filed generated on the bullet

itself due to the charge separation and (2) Coulomb repulsion force due to the inner

surface ions of the micro-nozzle, which are obliquely imploding toward the

symmetric axis along which the bullet protons are accelerated. The lateral expansion

of the accelerated protons is well suppressed by the imploding micro-nozzle plasma

and result in low divergence and high kinetic energies. A simple analytical model is

also provided to reveal the underlying physics.