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arXiv · 2305.09581

Energy Depletion and Re-Acceleration of Driver Electrons in a Plasma-Wakefield Accelerator

F. Peña·C. A. Lindstrøm·J. Beinortaitė·J. Björklund Svensson·L. Boulton·S. Diederichs·B. Foster·J. M. Garland·P. González Caminal·G. Loisch·S. Schröder·M. Thévenet·S. Wesch·J. C. Wood·J. Osterhoff·R. D'Arcy
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Abstract

For plasma-wakefield accelerators to fulfil their potential for cost effectiveness, it is essential that their energy-transfer efficiency be maximized. A key aspect of this efficiency is the near-complete transfer of energy, or depletion, from the driver electrons to the plasma wake. Achieving full depletion is limited by the process of re-acceleration, which occurs when the driver electrons decelerate to non-relativistic energies, slipping backwards into the accelerating phase of the wakefield and being subsequently re-accelerated. Such re-acceleration is unambiguously observed here for the first time. At this re-acceleration limit, we measure a beam driver depositing (57 $\pm$ 3)\% of its energy into a 195-mm-long plasma. Combining this driver-to-plasma efficiency with previously measured plasma-to-beam and expected wall-plug-to-driver efficiencies, our result suggests that plasma-wakefield accelerators can in principle reach or even exceed the energy-transfer efficiency of conventional accelerators.

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F. Peña, C. A. Lindstrøm, J. Beinortaitė, J. Björklund Svensson, L. Boulton, S. Diederichs, B. Foster, J. M. Garland, P. González Caminal, G. Loisch, S. Schröder, M. Thévenet, S. Wesch, J. C. Wood, J. Osterhoff, R. D'Arcy. 2023-05-16. Energy Depletion and Re-Acceleration of Driver Electrons in a Plasma-Wakefield Accelerator. https://doi.org/10.1103/physrevresearch.6.043090

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