BEAMS
In the literature: open
Damage mechanism of dielectrics under picosecond wakefields
In plain words
Dielectric tubes driven by very short electron bunches survive fields far above what copper tolerates, then fail at a threshold whose cause is unclear.
Precise statement
Fused-silica and diamond structures driven by sub-picosecond electron bunches (sigma_z ~ 2e-3 to 1e-2 cm) sustained surface fields of order $eE \sim 100\ \mathrm{MeV}/\mathrm{cm}$ before damage (SLAC experiments from 2008 onward). Determine the damage mechanism and its scaling with field duration from 0.1 to 10 ps and with band gap, separating field-induced ionization, heating by beam halo, and surface charging.
What would settle it
Threshold measurements versus pulse duration for at least two materials of different band gap, compared with ionization and heating models.