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Ultrafast electron dynamics determines how physical and chemical changes occur at a fundamental level. The investigation of such processes requires (isolated) attosecond pulses [1]. On all time scales down to the attosecond regime, there are a number of physical processes that depend on the electric field, rather than just the intensity envelope of a driving pulse. There have been numerous proposals...
We perform Particle-In-Cell (PIC) simulation of KALI-30 GW pulsed power generator based rod-pinch diode. It is shown that ions emitted from the anode-plasma play a crucial role in diode dynamics. It is found that ions not only help in compensating the space charge due to electron beam, but also lead to enhancement of the local electric field at the side walls of the cathode leading to additional electron...
A Flash X-ray diode has been designed and developed for generation of single shot, nanosecond duration x-rays from KALI-5000 Pulse Power System (0.8-1 MV, 40 kA, 100 ns). The typical electron beam parameter was 500 kV, 8 kA, 100 ns, with a few hundreds of A/cm current density. The spot size for different diode configurations varied from 4 mm to 2 mm. X-ray radiograph of various metal objects were...
An alternative free electron laser concept for producing coherent terahertz radiation is investigated. A weakly relativistic electron beam impinged on a rippled underdense plasma, at an angle to the ripple wave vector, interacts with a seed terahertz signal to produce a space charge beam mode. The oscillatory electron velocity due to the beam mode beats with the density ripple to generate a coherent...
A pulse power system (1 MV, 5 0kA, and 100 ns) based on dual polarity charged Marx generator and Blumlein pulse forming line (PFL) was built to generate high power microwaves. This paper describes the inherent prepulse present with the Blumlein configuration and the mitigation strategies adopted. Further, a qualitative attempt to verify the generation of high power microwave output on the system is...
Summary form only given. Intense relativistic electron beam generation studies were carried out in a planar diode configuration to investigate the effect of the plasma expansion on the impedance characteristics of the diode. The diode voltage and current waveforms were analyzed with the bipolar space-charge limited flow model. The anode and cathode plasma expansion velocities were calculated using...
Summary form only given. Intense gigawatt relativistic electron beam generation studies were carried out in the presence of prepulse. Electron beams were generated using planar and annular graphite cathodes of various diameters. At 25 mm anode-cathode gap beam parameters obtained are 386 kV, 25 kA, 100 ns. A bipolar prepulse voltage has been recorded at the diode for both the cathodes. Amplitude of...
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