Could vacuum physics be revealed by laser-driven microbubble?<http://www.spacedaily.com/reports/Could_vacuum_physics_be_revealed_by_laser_driven_microbubble_999.html>
Scientists at Osaka University discovered a novel mechanism which they refer to as microbubble implosion (MBI) in 2018. In MBI, super-high energy hydrogen ions (relativistic protons) are emitted at the moment when bubbles shrink to atomic size through the irradiation of hydrides with micron-sized spherical bubbles by ultraintense, ultrashort laser pulses. In this study, the group led by Masakatsu Murakami confirmed that during MBI, an ultrahigh electrostatic field close to the Schwinger field could be achieved because micron-sized bubbles embedded in a solid hydride target implode to have nanometer-sized diameters upon ionization.