  This study is designed to explore the two dimensional temperature maps of the
atmospheric argon discharge consisting of pin-to-plane electrodes supplied by a
high voltage DC source. After checking the stability of the micro discharge,
the two dimensional image plane focused by a quartz lens was scanned by the
fiber probe driven by a 3D Mobile Platform. The rotational and vibrational
temperatures are calculated using nitrogen emissions collected by the high
resolution spectrometer and high sensitive intensified charge coupled device
(ICCD). The rotational temperature varies from 1558.15 K to 2621.14 K and
vibrational temperature varies from 3010.38 K to 3774.69 K, indicating a great
temperature gradient due to small discharge size. The temperature maps show a
lateral expansion and a sharp truncation in the radial direction. A double
layers discharge is identified, where an arc discharge coats the glow
discharge.
