Laser ionization based on resonance saturation—a simple model description

Measures, Raymond M.; Cardinal, P. G.

doi:10.1103/physreva.23.804

Cited by 108 publications

(31 citation statements)

References 28 publications

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“…Both cascade and multiphoton ionization require high laser intensities, usually in excess of 10 8 W=cm 2 . In solids, or in the presence of a solid surface, breakdown intensities as low as 10 6 W=cm 2 have been observed [11]. In transparent solids, this has been attributed to nonlinear selffocusing [11].…”

Section: Overview Of Thermal Thruster Physicsmentioning

confidence: 97%

Laser Propulsion for Ground Launch

Resendes¹,

Mota²,

Mendonça³

et al. 2007

Journal of Propulsion and Power

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Ground-to-orbit launch using laser propulsion requires a thermal system. A number of such thermal thruster concepts have been developed in the past. Thus far, only the laser-supported detonation thruster concept has led to a flight vehicle, the Lightcraft. It is shown via flight simulations and measurements with the Lightcraft that there are no inherent limitations for a ground-to-orbit launch vehicle using laser propulsion. A planar geometry laser-supported detonation thruster using a CO 2 laser is considered and its performance evaluated. A 10-km height flight vehicle using existing lasers is proposed. Nomenclaturespecific enthalpy of gas, height h P = Planck's constant h lsr = laser site altitude h ref = atmospheric scale height I abs = laser intensity absorbed by gas I sp = specific impulse k = absorption coefficient k B = Boltzmann's constant m = mass _ m= mass flow rate n X = number density of X P = power p = pressure q = specific heat added to gas r = radius r hot spot = vehicle hot-spot radius r lsr = laser main deflector radius T = temperature u = velocity in shock-fixed reference frame v = velocity in laboratory reference frame abs = atmospheric absorption coefficient R slant = slant range = efficiency = semivertex angle = longitude = wavelength = density = laser frequency = latitude e = Earth's rotational velocity

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Section: Overview Of Thermal Thruster Physicsmentioning

confidence: 97%

Laser Propulsion for Ground Launch

Resendes¹,

Mota²,

Mendonça³

et al. 2007

Journal of Propulsion and Power

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“…An alternative way for a dense gas layer ionization is LIBORS technique (Laser Ionization Based On Resonance Saturation) [11][12][13]. A resonant dye-laser radiation provides a high non-Boltzmann population of the corresponding state.…”

Section: Catalytic Resonance Ionization As a Technique For Multi-compmentioning

confidence: 99%

“…A more effective way to produce the plasma is by a two-step process [7,8] , where first a neutral gas cloud is produced in one way or another (e.g. by laser radiation) which then can be ionized by means of laser produced shock waves [7], an external UV-fiashlamp [8,9], or a near-surface discharge [10].An alternative way for a dense gas layer ionization is LIBORS technique (Laser Ionization Based On Resonance Saturation) [11][12][13]. A resonant dye-laser radiation provides a high non-Boltzmann population of the corresponding state.…”

mentioning

confidence: 99%

Experiments on catalytic resonance ionization of dense tantalum-contained ruby-laser-produced gas clouds with a KrF laser

et al. 1995

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In this paper we describe the principle of a technique to produce planar and volumetric plasma sources of nearly every element and results of experiments on verification of this technique. This technique is based on a generalization of the LIBORS-process (Laser Ionization BAsed On Resonant Saturation) which because of its similarity to chemical catalytic reactions has been called CATRION (CATalytic Resonance IONization). Characteristics of vapor clouds formed near wide variety of mono-or two-component targets in vacuum with a pulsed ruby laser were investigated. Effect of an intense KrF laser radiation on expanding tantalum-contained and, for comparision, titanium vapor clouds was studied. Photoresonance ionization in saturation mode of tantalum cloud was detected with the help of a frame camera, Langmuir probes and spectroscopic diagnostics. CATALYTIC RESONANCE IONIZATION AS A TECHNIQUE FOR MULTI-COMPONENT PLASMA PRODUCTIONMany industrial and scientific applications require the production of spatially localized plasma layers near to or in contact with material surfaces in vacuum. For example, such layers are needed in the formation of plasma electrodes for laser ion sources [1 2] and in different types of high power accelerators [3][4][5] . A standard way for the production of the plasma layers is to illuminate a suitable material surface with intense non-resonant laser radiation [6]. At sufficiently high exposure levels a "laser plasma" with a relatively small number of particles but with high ion-temperatures is formed. A more effective way to produce the plasma is by a two-step process [7,8] , where first a neutral gas cloud is produced in one way or another (e.g. by laser radiation) which then can be ionized by means of laser produced shock waves [7], an external UV-fiashlamp [8,9], or a near-surface discharge [10].An alternative way for a dense gas layer ionization is LIBORS technique (Laser Ionization Based On Resonance Saturation) [11][12][13]. A resonant dye-laser radiation provides a high non-Boltzmann population of the corresponding state. Then through high-frequency super-elastic collisions of seed electrons with excited atoms and stimulated bremsstrahlung absorption the radiation energy is transferred to free electrons. Eventually after a subsequent chain of events, the gas becomes ionized practically fully. The advantages of The LIBORS-method (in contrast to "laser plasma" ) is a more effective use of the available laser energy for ionization, and a low temperature of the resulting plasma ions. However, the necessity of a tunable flashlamp-pumped dye laser for the resonant excitation of the vapor limits its practical usefulness. However, due to the photochemical instability of dye lasers [14] and strong thermo-optical distortion of dye solutions they are unsuitable for operation at high repetition rates and for long time periods. In addition, to ionize different atoms one must change from one dye solution to another and tune a dispersive element of the laser. Furthermore, the resonance transitions o...

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“…The rate coecient k nm and k mn have been taken from Ref. [15]. For the radiative recombination rate coecient we have used the empirical formula given by Drawin [28].…”

Section: Lithium Datamentioning

confidence: 99%

“…These studies provide insight into (i) the ionization mechanism, (ii) energy transfer mechanisms which are implied in or serve the ionization. Plasma formation in these experiments has been explained in terms of a propagating loop of superelastic collisions between neutral atoms and seed electrons [14,15]. The electrons gain kinetic energy * corresponding author; e-mail: hameideg@yahoo.com in collisions with excited atoms and start runaway collisional ionization process.…”

Section: Introductionmentioning

confidence: 99%

Collisional Ionization in Lithium Vapor Excited by Nanosecond Laser Pulses

2012

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We report a theoretical study of the collisional ionization processes which occur under 2s → 2p excitation of lithium vapor excited with a nanosecond pulsed laser. The time evolution of the electron energy distribution function and the atomic ion density (Li + ) as well as the molecular ion density (Li + 2 ) at dierent lithium vapor densities was investigated. The results show a nonlinear behavior of the energy spectra of the electrons created during the interaction of the laser with the lithium vapor. The nonlinear behavior results from superelastic collisions between the free electrons produced by collisional ionization and photoionization with Li(2p). The results also show that a competition exists between the collisional ionization and photoionization processes in producing the atomic ion and the molecular ions.

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Laser ionization based on resonance saturation—a simple model description

Cited by 108 publications

References 28 publications

Laser Propulsion for Ground Launch

Laser Propulsion for Ground Launch

Experiments on catalytic resonance ionization of dense tantalum-contained ruby-laser-produced gas clouds with a KrF laser

Collisional Ionization in Lithium Vapor Excited by Nanosecond Laser Pulses

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