  The formation of self-consistent dust crystal and its melting is a well known
phenomenon in rf generated plasma but remains challenging in DC glow discharge
plasma. Here, we report the melting of a two dimensional dusty plasma crystal,
suspended in the cathode sheath of a DC glow discharge plasma. The experiments
are carried out in a $\Pi-$shaped Dusty Plasma Experimental (DPEx) device where
a stationary crystal of melamine formaldehyde particles is formed between the
confining strips in a background of Argon plasma. The stable structure breaks
and leads to a fluid state on reducing the neutral pressure.% and even reaches
to a gas like states at very low pressure. The neutral pressure range where
this melting transition is observed is an order of magnitude less than what
reported in rf discharge plasma. The transition is confirmed by evaluating the
variation in different characteristic parameters such as the pair correlation
function, voronoi diagram, local bond order, defect fraction and dust
temperature as a function of background neutral pressure. The transition is
attributed to an increase in effective particle temperature which we believe is
occurred due to increase in charge fluctuation and ion streaming. The special
feature of the device that helps formation of dust crystal and its melting in
DC glow discharge can be implemented to study various phenomena associated with
dust crystal in dc glow discharge plasma devices.

Plasma Physics