Intense electron emission from cathodes that provide very high current densities (several kA/cm2) is necessary for a various pulsed power applications. This contribution presents a quantitative analyses of the following processes and inherent physics: (a) Local field enhancements at micro-protrusions, (b) role of ion/ions near the emitting surface in lowering and thinning the potential barrier which increases emission. (c) localized heating at cathode tips that could produce hot-electrons and hot-phonons, ultimately leading to localized melting. Temperatures are predicted to possibly reach the cathode melting point on the nanosecond time scales. This is in keeping with the explosive emission phenomenon that is well known.