Characteristics of cryoplasma below boiling temperature of N$_2$

Cryogenic plasmas, whose gas temperatures are below room temperature, possess interesting characteristics. The temperature dependences of fundamental characteristics of cryoplasma were studied in detail. We used two types of parallel plate electrodes and the ambient He gas temperature was set to values less than boiling temperature of N$_2$. The breakdown voltage and excited species changed drastically at a temperature of {40 K}. Two discharge modes (Townsend and glow mode) were observed by current-voltage measurements and the power consumption in the Townsend mode was confirmed to be lower than {30~mW}.