Ponderomotive-expulsion: toward creating an electron-free volume

Fuente: arXiv
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Autores principales: Ravichandran, Smrithan, Cebriano, Teresa, Henares, José Luis, Mendez, Cruz, Pérez-Hernández, José Antonio, Roso, Luis, Fedosejevs, Robert, Hill III, Wendell T.
Formato: Preprint
Publicado: 2025
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author Ravichandran, Smrithan
Cebriano, Teresa
Henares, José Luis
Mendez, Cruz
Pérez-Hernández, José Antonio
Roso, Luis
Fedosejevs, Robert
Hill III, Wendell T.
author_facet Ravichandran, Smrithan
Cebriano, Teresa
Henares, José Luis
Mendez, Cruz
Pérez-Hernández, José Antonio
Roso, Luis
Fedosejevs, Robert
Hill III, Wendell T.
contents We describe a demonstration of a prototype approach to clear the laser focal volume of free electrons and disable their atomic and molecular sources. Employing two temporally separated, copropagating pulses, we exploited a pump-probe setup in our experiment. The pump ionized a low-density gas and expelled free and nascent electrons from its focal volume. The probe, traversing the same focal volume, expelled any remaining free and probe-induced nascent electrons. We gauged the effectiveness of the approach by capturing the spatial distribution of ejected electrons with image plates while we varied the relative intensity and time delay between the pump and probe. When we injected the pump 300 fs before the probe, we found the electron spatial distribution significantly altered and the yield suppressed, proving ponderomotive expulsion works. However, the yield was enhanced when we set the temporal spacing between the pump and probe to 150 fs. Simulations show the enhancement is due to Airy rings of the focused pump expelling electrons inward toward the propagation axis. Our results show that the complete removal of focal-volume electrons was inhibited by spatial overlap fluctuations and the stronger probe generating ionization outside the cleared-volume of the pump. We discuss ways to mitigate these impediments and propose alternate two-beam arrangements to achieve more efficient focal-volume clearing.
format Preprint
id arxiv_https___arxiv_org_abs_2505_04582
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Ponderomotive-expulsion: toward creating an electron-free volume
Ravichandran, Smrithan
Cebriano, Teresa
Henares, José Luis
Mendez, Cruz
Pérez-Hernández, José Antonio
Roso, Luis
Fedosejevs, Robert
Hill III, Wendell T.
Instrumentation and Detectors
Applied Physics
Plasma Physics
We describe a demonstration of a prototype approach to clear the laser focal volume of free electrons and disable their atomic and molecular sources. Employing two temporally separated, copropagating pulses, we exploited a pump-probe setup in our experiment. The pump ionized a low-density gas and expelled free and nascent electrons from its focal volume. The probe, traversing the same focal volume, expelled any remaining free and probe-induced nascent electrons. We gauged the effectiveness of the approach by capturing the spatial distribution of ejected electrons with image plates while we varied the relative intensity and time delay between the pump and probe. When we injected the pump 300 fs before the probe, we found the electron spatial distribution significantly altered and the yield suppressed, proving ponderomotive expulsion works. However, the yield was enhanced when we set the temporal spacing between the pump and probe to 150 fs. Simulations show the enhancement is due to Airy rings of the focused pump expelling electrons inward toward the propagation axis. Our results show that the complete removal of focal-volume electrons was inhibited by spatial overlap fluctuations and the stronger probe generating ionization outside the cleared-volume of the pump. We discuss ways to mitigate these impediments and propose alternate two-beam arrangements to achieve more efficient focal-volume clearing.
title Ponderomotive-expulsion: toward creating an electron-free volume
topic Instrumentation and Detectors
Applied Physics
Plasma Physics
url https://arxiv.org/abs/2505.04582