Fig. 5
From: Generation of giga-electron-volt proton beams by micronozzle acceleration
Upper row: 2D profiles of the longitudinal electric fields \(E_x\) (compare Fig. 1). Lower row: proton density profiles at different times, at sequential times, \(t= 230, 250\), and 270 fs for the MNA target, which correspond to the early times of the afterburner phase; \(n_c\) denotes the critical density. The head protons are observed to be continuously accelerated by the comoving electric field. Applied laser and target conditions are the same as in Fig. 3.
