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Updated: Mar 1, 2026
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Investigation of Early Plasma Evolution Induced by Ultrashort Laser Pulses
Published on: July 2, 2012
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Relativistic Electron Streaming Instabilities Modulate Proton Beams Accelerated in Laser-Plasma Interactions
S Göde1,2, C Rödel1,3, K Zeil4
1High Energy Density Science Division, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
Physical Review Letters
|May 27, 2017
Summary
Strong electromagnetic fields modulate high-energy protons during laser-plasma interactions. These modulations, driven by rear-side preplasma, are crucial for controlling proton acceleration in various applications.
Area of Science:
- Plasma Physics
- High-Energy-Density Physics
- Laser-Matter Interactions
Background:
- Relativistic laser-plasma interactions can accelerate multi-MeV protons.
- The development of preplasma on target rear sides is a critical factor in these interactions.
- Understanding electromagnetic field generation and its impact on particle acceleration is essential.
Purpose of the Study:
- To experimentally investigate the modulation of multi-MeV protons by filamentary electromagnetic fields in relativistic laser-plasma interactions.
- To characterize the strength and scale of these electromagnetic fields.
- To determine the influence of target preplasma on proton modulation and acceleration.
Main Methods:
- Experimental observation of multi-MeV proton spatial profiles from laser-irradiated hydrogen targets.
- Utilizing relativistic electron Weibel instability for electromagnetic field amplification.
- Comparison of experimental data with three-dimensional particle-in-cell simulations and analytical estimates.
Main Results:
- Experimental evidence of proton modulation by strong filamentary electromagnetic fields (B>10 MG, E>0.1 MV/μm) with μm-scale wavelength.
- Modulations are observed when a preplasma is present on the rear side of the target.
- The process is confirmed to be dominant for various target materials if rear-side preplasma scale length meets specific criteria (≳0.13λ₀√(a₀)).
Conclusions:
- Strong electromagnetic fields generated via Weibel instability in laser-produced preplasmas significantly modulate accelerated protons.
- The presence and scale length of rear-side preplasma are critical parameters for achieving controlled proton modulation and acceleration.
- These findings provide essential constraints for optimizing proton acceleration in laser-plasma experiments for diverse applications.
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