FUNDAMENTALS AND APPLICATION OF AN EXPANDING HYDROGEN LOW-PRESSURE PLASMA-JET

The absolute density of atomic hydrogen excited states in two differen t regimes of a magnetized expanding plasma is determined using emissio n and absorption spectroscopy. First evidence has been found for the p resence of high densities of negative ions in the ''atomic'' (recombin ing) regime of an expanding hydrogen plasma. Several clear observation s of the presence of ''hot'' electrons have been made in the ''molecul ar'' (ionizing) regime of the expanding plasma. For both regimes the a bsolute density of atomic hydrogen in the ground state and the degree of plasma dissociation have been determined. Copyright (C) 1996 Elsevi er Science Ltd.