On self-organized structures and two electron temperatures in aspatially inhomogeneous plasma

Characterization and study of self-organized complex potential structure formation is performed in DC glow discharge plasma in absence of any externally applied magnetic or electric field. The study is done using a spherical electrode of ~5cm diameter and two copper plates of bigger size than the spherical electrode in high pressure. Formation of local potential structures is visually observed after a certain value of applied of DC power. The experiment is carried out in nitrogen gas environment with working pressure ~0.1mbar. The measurements of I-V characteristics at different positions w.r.t the spherical electrode and corresponding analysis according to the four-parameter model indicates the presence of energetic species. The presence of a kHz range frequency in the Fast Fourier Transform (FFT) analysis indicates the possibility of presence of oscillations which can be a candidate for the formation of instability and self- organization of complex potential structures. The experimental results and presence of two electron temperatures in high pressure glow discharge (HPGD) plasma is reported here. (author)