| dc.description.abstract | This study dives into the basics of laser-driven radiation pressure acceleration (hole-boring RPA) and its acceleration mechanism, using simulations to see how well the theory works with gaseous targets. Most existing theories focus on solid targets, but we switched things up by looking at gaseous ones, exploring how factors like target density and thickness play a role. We worked out the velocity and ion energy of the hole-boring RPA mechanism using momentum conservation, dug into the effects of relativity, and explained how the double-layer structure forms and stays stable. We also looked at how laser settings—like intensity, frequency, and polarization—impact proton acceleration.
To test these ideas and uncover more details, we used numerical simulations with the Particle-in-Cell (PIC) method. The results show that the double-layer structure between electrons and protons is crucial for producing high-quality proton beams. By tweaking the laser’s elliptical polarization, we could suppress oscillations in the double-layer structure and boost the energy concentration of the proton beam. But here′s where it gets interesting: as the laser intensity increased, the allowable range for elliptical polarization didn’t shrink like the theory said—it actually got bigger.
We also found some surprising patterns with electron temperature. When the double-layer structure worked well, the temperature leveled off over time and followed a logarithmic trend. But when it broke down, the temperature shot up exponentially. This shows that heating timescales are a big deal for stability—something the current theories don’t fully cover.
On top of that, we saw big differences in how different target densities handled elliptical polarization. This suggests the current theories might not work as well for low-density targets. We hope our work helps refine these theories and pin down better conditions for elliptical polarization.
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