Marrying ring-shaped structures from laser plasma interactions to their formation mechanism
Marrying ring-shaped structures from laser plasma interactions to their formation mechanism lead image
The propagation of a high-power short-pulse laser in low-density plasma is relevant to the laser-driven acceleration of charged particles, developing hard electromagnetic radiation, nuclear fusion, and other applications. However, ring-shaped electromagnetic and electron structures that form during this interaction can limit efficiency and damage equipment.
Valenta et al. analytically described the formation mechanism of ring-shaped electromagnetic and electron structures. They found the electromagnetic rings appear when the laser pulse is defocused by the excitation of Langmuir waves in underdense plasma. Wakefields of the electromagnetic rings then form and accelerate the ring-shaped electron beams.
The authors used 3D numerical simulations to demonstrate that tweaking laser and plasma parameters can tune the properties of electromagnetic rings.
“The knowledge of physical mechanisms that lead to the formation of electromagnetic and electron rings, as well as how these structures can be controlled, can be directly used for advancing applications based on the laser and plasma interaction,” said author Petr Valenta. “Also, there are potential applications that could benefit from the controlled generation of electromagnetic and electron ring structures.”
Electromagnetic rings could be used to drive the plasma acceleration of electrons and positrons. Similarly, the electron ring structures could also act as drivers for the plasma acceleration of positrons, as well as a source of high-flux X-rays and compact collimators for proton bunches in radiofrequency accelerators.
Next, the authors will experimentally measure the relationships between the properties of ring-shaped electromagnetic and electron beam structures and the laser plasma parameters that were explored via simulation in this work. These measurements can then be used to develop a new diagnostic for determining laser plasma interaction regimes.
Source: “On the electromagnetic-electron rings originating from the interaction of high-power short-pulse laser and underdense plasma,” by P. Valenta, G. M. Grittani, C. M. Lazzarini, O. Klimo, and S. V. Bulanov, Physics of Plasmas (2021). The article can be accessed at https://aip.scitation.org/doi/full/10.1063/5.0065167 .
