Fig. 1. Simplified schematic top-view of the experimental setup within (a) and outside (b) the vacuum target chamber.

Fig. 2. Schematics of the various copper target configurations used: (a) thick copper block target grounded by a massive metal stalk, (b) 1 mm thick rectangular target grounded by an inductive current probe and 10 mm copper braid, (c) 1 mm thick rectangular target coupled to an inductive current probe and a 50 coaxial cable and (d) 1 mm thick rectangular target separated from the ground by an insulator with a length of 40 mm and capacity of 6 pF.

Fig. 3. (a) Time-resolved B-dot raw signal from the shot with 5 mm thick copper bar and laser energy of 602 J. The upper graph has a time base of 120 ns, while the lower graph shows a zoomed-in view of the same signal with a 3 ns time range. The points represent the signal samples with a rate of 128 GS/s. (b) Time-resolved waveform of the B-field obtained from the B-dot signal from the same shot as (a).

Fig. 4. Intensity scaling of the B-field within the vacuum chamber at a distance 39 cm from the target.

Fig. 5. Comparison of B-dot signal FFT spectra for different target geometries (see Figures 2(a) and 2(b)) for the 5 mm thick target and the 1 mm thick grounded target. For each target geometry the laser energy is varied.

Fig. 6. Demonstration of the repeatability by average B-dot signal spectra from a group of shots in terms of energy and peak power – black line: shots with 150–190 J and 0.4–0.7 TW; blue line: shots with approximately 280 J/1 TW; and red line: shots with 500–600 J and 1.6–2.0 TW.

Fig. 7. Comparison of D-dot signal FFT spectra for different target geometries (see Figures 2(a) and 2(b)) for the 5 mm thick target and the 1 mm thick grounded target.

Fig. 8. Intensity scaling of the E-field maximum within the vacuum chamber at a distance 41 cm from the target, measured with a D-dot probe.

Fig. 9. Comparison of EMP signal spectra detected outside the target chamber.

Fig. 10. Comparison of inductive probe signals from a series of shots at different energies. The left-hand column displays raw signals proportional to the time derivative of the target current, while the right-hand column shows target currents obtained by integrating the probe signals.

Fig. 11. Comparison of the FFT spectra of the inductive target current probe signals from shots with different energies.

Fig. 12. Scaling of the target current maximum and spectrum central frequency as a function of the laser peak power.

Fig. 13. (a) Comparison of the target voltage signal obtained from a series of shots at different energies. (b) Scaling of the target voltage maximum with the laser peak power.

Fig. 14. Comparison of the target voltage spectra obtained from shots with different energies.

Fig. 15. Energies of the signals of the EMP detector used as a function of the laser peak power.

Fig. 16. Exemplary electron spectra from the shot with the copper bar target and laser peak power of 2.2 TW (energy of 613 J).

Fig. 17. Angular distribution of electron temperature (a) and fluence (b), and electron fluence as a function of the absolute value of the emission polar angle (c), in the energy range of 50 keV–2 MeV, measured during a shot with a peak power of 2.2 TW (corresponding to an energy of 613 J).

Fig. 18. Energies of the signals of the EMP detector used as a function of the number of emitted electrons.

Fig. 19. Amplitude of the first period of the biconical antenna signal in dependence on the laser peak power (a) and number of emitted electrons (b).

Fig. 20. Spectrograms (STFT) of EMP signals from shots: 250 J and grounded target, 602 J and grounded target and 663 J with insulated target.

Fig. 21. Time-resolved plasma expansion in the shot with the laser pulse energy of 506 J and duration of 309 ps taken by the microchannel plate X-ray pinhole camera.

Fig. 22. Testing of the inductive target current probe using an electrical pulse generator.

Fig. 23. Frequency characteristic of the high-voltage target voltage probe.

Fig. 24. Schematic visualization of the double-ridged horn antenna.

Fig. 25. Typical gain of the double-ridged horn antennas, Rohde & Schwarz HF-906 and HF-907, given by the manufacturer.

Fig. 26. In situ cross-calibration of horn antennas HF-906 and HF-907: comparison of signals in the time domain (a) and frequency domain (b).

Fig. 27. Specific attenuation of the coaxial cables.