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Title: Suppressing electron-beam shot noise below the random level
Plain: Electrons arrive at random, which seeds noisy x-ray output and harmful instabilities; collective forces can make them more evenly spaced than random, but only at long wavelengths so far.
Precise: Coulomb repulsion acting over a quarter plasma period in a drift can reduce beam density fluctuations below the Poisson shot-noise level. Determine whether suppression by more than 10 dB can be produced and kept through acceleration and compression at wavelengths below 1e-5 cm, which would reduce SASE start-up noise and microbunching gain.
Settled by: Measured coherent radiation from a beam below the shot-noise level at the stated wavelength after acceleration and compression.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: partially-resolved
Status note: Sub-shot-noise density fluctuations were reported at optical wavelengths in the 2010s; suppression at XUV and x-ray wavelengths is undemonstrated.
Posed since: (empty)