Role of chirp in electron emission from liquid droplet microplasma

Abstract

Electron emission from microdroplets subjected to a distortion in its spherical shape by a pre-pulse is studied, especially to decipher the role of chirp in the laser pulse. While there are some noticeable differences in the spectral shape with sign of the chirp, the change in the average electron energy is small. Increase in the pulse width diminishes the electron emission propensity and also the average electron energy. Analytical formalism on the two-plasmon decay instability identified to be responsible for the electron emission provides insight to explain the measurements. Electron emission computed by 2D particle-in-cell simulations for these experiments compares very well with the measurements.