O. N. Rosmej1、2、3、a), X. F. Shen4, A. Pukhov4, L. Antonelli5, F. Barbato6, M. Gyrdymov2, M. M. Günther1, S. Zähter1, V. S. Popov7、8, N. G. Borisenko9, and N. E. Andreev7、8
Author Affiliations
1GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt, Germany2Goethe University, Frankfurt, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany3Helmholtz Forschungsakademie Hessen für FAIR (HFHF), Campus Frankfurt am Main, Max-von-Laue-Straße 12, 60438 Frankfurt am Main, Germany4Heinrich-Heine-University Düsseldorf, Universitätsstraße 1, Düsseldorf, Germany5York Plasma Institute, University of York, Church Lane, Heslington, York YO10 5DQ, United Kingdom6University of Bordeaux, CNRS, CEA, CELIA, UMR 5107, F-33405 Talence, France7Joint Institute for High Temperatures, RAS, Izhorskaya St. 13, Bldg. 2, 125412 Moscow, Russia8Moscow Institute of Physics and Technology (State University), Institutskiy Pereulok 9, 141700 Dolgoprudny, Moscow Region, Russia9P. N. Lebedev Physical Institute, RAS, Leninsky Prospekt 53, 119991 Moscow, Russiashow less
DOI: 10.1063/5.0042315
Cite this Article
O. N. Rosmej, X. F. Shen, A. Pukhov, L. Antonelli, F. Barbato, M. Gyrdymov, M. M. Günther, S. Zähter, V. S. Popov, N. G. Borisenko, N. E. Andreev. Bright betatron radiation from direct-laser-accelerated electrons at moderate relativistic laser intensity[J]. Matter and Radiation at Extremes, 2021, 6(4): 048401
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Fig. 1. Betatron radiation is generated when relativistic electrons undergo transverse betatron oscillations in self-generated quasistatic electric and magnetic fields.
Fig. 2. (a) Energy distribution of super-ponderomotive electrons per steradian measured at 0° (red), 15° (green), and 45° (blue) to the laser propagation direction for a shot onto a pre-ionized foam layer at 2 × 1019 W/cm2 laser intensity. (b) PIC simulations for the same interaction parameters. Reprinted with permission from Rosmej et al., Plasma Phys. Controlled Fusion 62, 115024 (2020). Copyright 2020 Author(s), licensed under a Creative Commons Attribution 4.0 License.
Fig. 3. (a) Spectral distribution of the betatron radiation simulated for the PHELIX parameters. (b) 2D map of the photon fluence at the detector placed at a distance of 120 cm from the source.
Fig. 4. Comparison of line out for different distances from R0 = 5 to R0 = 50 cm. The total distance R0 + R1 = 120 cm. The highest phase enhancement was observed at R0 = 15 cm.
Fig. 5. (a) Simulated XPCI radiograph. (b) Line out along the sphere axis [red dashed line in (a)]. The presence of phase enhancement is clearly visible around the sphere. We considered the betatron emission up to 40 keV and the sensitivity curve of the BAS-TR IP. For the x-ray source size, the worst case was assumed (an initial laser spot size of 15 µm).
Fig. 6. Comparison between (a) absorption and (b) XPCI. The line out across the cylinder axis in (c) reveals the contribution of phase enhancement to the detection of the sphere, absorption by which is otherwise too weak to allow its detection under standard noisy experimental conditions.
Laser/target | Regime | Electrons | X-rays | Brilliance | References |
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ASTRA-GEMINI 50 fs, 5 J, 35 µm a0 ≃ 2 Ne ≃ 1018 cm−3 | Resonant betatron oscillations in plasma wake; experiment | Emax ≃ 700 MeV Qe N/A | Nph ≃ 5 × 108Ec ≃ 50–450 keV = 14 mrad Source size LRMS ≃ 15 µm | 1023 | 12 | TITAN 0.7 ps, 120 J, 20 µm a0 ≃ 3 Ne ≃ 1019 cm−3 supersonic gas-jet | SMLWFA; experiment | Thot ≃ 15 MeV Emax ≃ 300 MeV Qe ≃ 10 nC | Nph ≃ 109 eV−1 sr−1 ΔEph ≃ 6.5 ± 0.5 keV Ec ≃ 10 keV = LRMS ≃ 35 µm | N/A | 17 and 18 | PETAL 0.5 ps, 1 kJ, 42 µm a0 ≃ 7.5 Ne ≃ (1–3) × 1018 cm−3 cm-long plasma | SMLWFA; CALDER-CIRC simulations | Ee ≃ 1 GeV Qe ≃ 38 nC (>70 MeV) | Nph ≃ 7 × 1011 ΔEph ≃ 2–60 keV Ec ≃ 10 keV = 50 mrad LRMS ≃ 25 µm | 5 × 1020 | 8 | PHELIX 0.7 ps, 80 J (EFWHM ≃ 20–30 J), 15 µm a0 ≃ 3–4 Ne ≃ 0.6 × 1021 cm−3 pre-ionized low-density polymer aerogels | DLA at betatron resonance; experiment and 3D PIC | Thot ≃ 13 MeV Emax ≃ 100 MeV Qe ≃ 1 µC (>2 MeV) Qe ≃ 100 nC (>7 MeV) experiment | Nph ≃ 6 × 1011 ΔEph ≃ 1–10 keV Nph ≃ 1011 (>10 keV) Ec ≃ 5 keV ≃ 700 mrad LRMS ≃ 4 µm 3D PIC | 6 × 1019 | 22 Current work |
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Table 1. Comparison of betatron sources produced in LWFA, SMLWFA, and DLA processes.