Experimental and Theoretical Study of Flow Dynamics of Expanding Hydrogen Plasma from an ECR Plasma Source

Priti Singh; Ramesh Narayanan; Ashish Ganguli; Debaprasad Sahu; Subhasish Bag

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arXiv · 2609.26070

Experimental and Theoretical Study of Flow Dynamics of Expanding Hydrogen Plasma from an ECR Plasma Source

Priti Singh·Ramesh Narayanan·Ashish Ganguli·Debaprasad Sahu·Subhasish Bag

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Abstract

The flow of moderately dense (n {\approx} 10^{11} cm^{-3}) hydrogen plasma with high electron temperature (T_{e} {\approx} 30 - 35 eV) and plasma potential (V_{p} {\approx} 100 V), expanding towards an expansion chamber (EC) from an ECR plasma source is investigated using Langmuir probes (LPs) and Ion Energy Analysers (IEAs). The LPs reveal presence of a second ionization zone (SIZ) a few centimetres from the ECR zone, indicating very short ionization mean paths, which are confirmed theoretically. The SIZ gives a density boost, produces a double layer, DL (ΔV_{DL} {\approx} 106 - 40 V) and a warm electron population after the DL (n_{w}/n {\approx} 0.04 - 0.10, T_{w} {\approx} 40 - 60 eV). IEA measurements conducted at two sites (z_{1} {\approx} 5 cm, z_{2} {\approx} 10 cm) reveal ions with energies in the range {\approx} 65 - 8 eV at pressures {\approx} 1 - 8 mTorr. DL formation is explained in terms of the SIZ and warm electron generation is analysed in detail.

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Priti Singh, Ramesh Narayanan, Ashish Ganguli, Debaprasad Sahu, Subhasish Bag. 2026-08-02. Experimental and Theoretical Study of Flow Dynamics of Expanding Hydrogen Plasma from an ECR Plasma Source. https://arxiv.org/abs/2609.26070

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