In the realm of energy and plasma physics, researchers are continually seeking to understand and harness the interactions between intense laser pulses and solid targets. These interactions can produce energetic proton and ion beams, which have potential applications in various fields, including proton beam therapy, materials modification, and nuclear physics. Among the researchers at the forefront of this field is Vasiliki E. Alexopoulou, who has been investigating these phenomena to derive predictive correlations between laser and target parameters and the resulting ion-beam properties.
Alexopoulou’s research, published in the journal [High Power Laser Science and Engineering], focuses on the Target Normal Sheth Acceleration (TNSA) mechanism, which is a process that generates energetic proton and ion beams when an intense laser pulse interacts with a solid target. Despite extensive experimental and theoretical efforts, predicting the properties of these ion beams has been challenging due to the complex and coupled nature of laser-plasma interactions. To address this, Alexopoulou employed a unified multiphysics model that accurately reproduces laser-solid interaction dynamics over a broad range of conditions.
Using this model, Alexopoulou derived statistically validated scaling laws and probability maps that correlate various ion-beam properties—such as cutoff energies, beam divergences, and ionization states of protons, carbon, and oxygen ions—to a wide set of laser and target parameters. These parameters include pulse duration, laser power, laser beam spot, target thickness, prepulse-main pulse interval, contrast, laser wavelength, and polarization. The research utilized multivariate regression with cross-validation to describe continuous beam properties and classification and regression tree (CART) methods to analyze discrete ionization states, capturing nonlinear and threshold-dependent behaviors.
The resulting scaling relations, contour maps, and box plots provide a predictive framework for understanding and optimizing laser-driven ion sources. This framework elucidates the coupled roles of laser pulse and target geometry in governing TNSA ion acceleration and charge-state formation. The findings offer valuable insights for the energy sector, particularly in applications requiring precise control over ion beam properties, such as proton beam therapy and materials modification. By understanding these correlations, researchers and engineers can better design and optimize laser systems for specific applications, potentially leading to more efficient and effective energy solutions.
This article is based on research available at arXiv.