Micro-discharge happens in a limited space. The gap spacing has the magnitude of sub-millimeters or below. Compared with the traditional gas discharge

micro-discharge has some unique characteristics due to the micro-scale and hence attracts a great amount of interest. On one hand

the micro-discharge system is easy to be miniaturized thus having great potential in applications such as biomedicine

micro-region thermal cooling

micro-electro-mechanical system

ionic blower

electrostatic-fluid accelerator

gas sensor

ion sources

liquid discharge technic

and electrostatic detection. On the other hand

accompanying with the rapid development of integrated circuits

micro-electronics technology and micro-electro-mechanical systems

the dimension of the conductor electrodes as well as the gap spacing between them has been sharply reduced. A possible risk comes from electrostatic discharge under low voltage breakdown that could turn to a hazard source for micro-electronics

initiate explosive materials or devices as well as electric power system. We review and summarize numerous experimental

computational and analytical works on micro-discharge and micro-plasma in recent years

and introduce progress in understanding the mechanisms and physics of micro-discharge and in the applications.