Population inversion in recombining hydrogen plasma

Furukane, Utarô; Yokota, Toshiaki; Oda, Toshiatsu

doi:10.1016/0022-4073(79)90114-6

Cited by 15 publications

(7 citation statements)

References 7 publications

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“…But the inversion disappears a little bit before the QSS is established at t = 10~8 s since n e exceeds the upper bound value for the generation of population inversion [9] as described before. In order to compare in more detail the above described three kinds of the results, we demonstrate the evolution of the overpopulation density An 32 (= n 3 /co 3 -n 3 /co 2 ) in Fig.…”

Section: Resultsmentioning

confidence: 70%

“…In case 1, n e0 is low, while it is high in case 2. The case 3 represents an extreme plasma whose electron density exceeds the upper bound value for the population inversion in the quasi-stationary state QSS [9]. This case is chosen in order to show whether the population inversion takes place in the transient phase of the recombining plasma whose electron density is so high that the population inversion cannot be expected in the QSS.…”

Section: ~(T H -T E )+ (R H+ -R E )mentioning

confidence: 99%

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Numerical Investigation of Laser Oscillation in a Recombining Hydrogen Plasma Interacting with Helium Gas in TPD-I

Oda

Furukane

1985

Zeitschrift Für Naturforschung A

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A numerical investigation on the basis of a collisional-radiative (CR) model has shown that laser oscillation between the levels with the principal quantum numbers ; = 2 and 3 can be generated in a recombining hydrogen plasma interacting with a dense helium gas as a cooling medium in TPD-I, which is a magnetically confined quiescent high-density plasma source consisting basically of two parts, namely, the discharge region with the cathode at the center of the cusped magnetic field and the plasma column region with the axial magnetic field. The population inversion is found to exceed significantly a threshold level for the laser oscillation even in the quasi-steady state when the hydrogen plasma with n t = 10 13 ~ 10 14 cm~3 interacts with the helium gas with a pressure of about 50 Torr.

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Section: Resultsmentioning

confidence: 70%

Section: ~(T H -T E )+ (R H+ -R E )mentioning

confidence: 99%

Numerical Investigation of Laser Oscillation in a Recombining Hydrogen Plasma Interacting with Helium Gas in TPD-I

Oda

Furukane

1985

Zeitschrift Für Naturforschung A

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“…The population inversion cannot be expected in the transient recombining phase, but is realized only in QSS and in the region for the electron density and temperature shown in [7][8][9].…”

Section: Resultsmentioning

confidence: 95%

“…At nto= 1014cnT3 (case III), however, the popula tion inversion is not produced till t -10~4s in the quasi-steady state. These facts indicate that the electron temperature and density of the plasma must be in the region for the inversion shown in [7][8][9] (for example, see Fig. 1 in [8]).…”

Section: T(s E C )mentioning

confidence: 99%

“…The region of the plasma parameters for gener ating the population inversion of the recombining plasma in QSS has been investigated by Bohn [7] and Furukane et al [8][9][10], For these recombining plasmas, the plasma conditions to obtain the high gains necessary for the laser oscillation have been also discussed by Bohn [7] and by Oda and Furu kane [11], Experimental investigations have been reported for generating population inversions between ex cited states of the hydrogen atom and hydrogen-like Reprint requests to Dr. U. Furukane. College of General Education.…”

Section: Introductionmentioning

confidence: 99%

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The Behaviour of Population in a Plasma Interacting with an Atomic Gas

Furukane

Oda

1984

Zeitschrift Für Naturforschung A

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The processes leading to the population inversion are investigated in a recombining hydrogen plasma which is interacting with a cool and dense neutral hydrogen gas by using the rate equations on the basis of a collisional-radiative (CR) model and the energy equations for electrons, ions and neutral particles. The quasi-steady state (QSS) approximation is used only for the levels i lying above a certain level /* which is not the first excited level. The calculations have shown that the quasi-steady state cannot be realized while intense energy-flows due to the collisional processes exist between different kinds of the particles such as the electrons and the ions in the plasma, and that the population inversion is realized only in the quasi-steady state following the transient phase. The effects of the initial conditions of the hydrogen plasma and of the introduced neutral hydrogen gas on the overpopulation density are also discussed.

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Collisional Radiative Models in Plasmas

Sijde

Mullen

Schram

1984

Contrib Plasma Phys

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A review on collisional‐radiative models in plasmas is given. Work of Fujimoto, Biberman et al, Drawin and Seaton has been an important guide to compose this review. Ionizing, recombining and equilibrium plasmas are dealt with. Attention has been paid to the classification of CR models in phases, such as Corona phase, excitation saturation phase (ESP), Capture radiative cascade (CRC) phase and partical local thermal equilibrium (PLTE). A numerical model applied to the argon neutral system and an analytical model applied to the ESP and PLTE for ionizing plasmas are treated in more detail.

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Population inversion in recombining hydrogen plasma

Cited by 15 publications

References 7 publications

Numerical Investigation of Laser Oscillation in a Recombining Hydrogen Plasma Interacting with Helium Gas in TPD-I

Numerical Investigation of Laser Oscillation in a Recombining Hydrogen Plasma Interacting with Helium Gas in TPD-I

The Behaviour of Population in a Plasma Interacting with an Atomic Gas

Collisional Radiative Models in Plasmas

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