Evolution from a Molecular Rydberg Gas to an Ultracold Plasma in a Seeded Supersonic Expansion of NO

Morrison, J. P.; Rennick, Chris; Keller, James S.; Grant, Edward R.

doi:10.1103/physrevlett.101.205005

Cited by 98 publications

(109 citation statements)

References 21 publications

(26 reference statements)

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“…700 mK, evolves to form a quasineutral ultracold plasma of NO + ions and electrons [6,7]. Present experiments measure the expansion and decay of this plasma by tracking its electron density waveform as a function of time-of-flight over adjustable intervals of distance.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

On the formation and decay of a molecular ultracold plasma

Saquet

Morrison

Schulz-Weiling

et al. 2011

J. Phys. B: At. Mol. Opt. Phys.

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Abstract.Double-resonant photoexcitation of nitric oxide in a molecular beam creates a dense ensemble of 50f (2) Rydberg states, which evolves to form a plasma of free electrons trapped in the potential well of an NO + spacecharge. The plasma travels at the velocity of the molecular beam, and, on passing through a grounded grid, yields an electron time-of-flight signal that gauges the plasma size and quantity of trapped electrons. This plasma expands at a rate that fits with an electron temperature as low as 5 K, colder that typically observed for atomic ultracold plasmas. The recombination of molecular NO + cations with electrons forms neutral molecules excited by more than twice the energy of the NO chemical bond, and the question arises whether neutral fragmentation plays a role in shaping the redistribution of energy and particle density that directs the short-time evolution from Rydberg gas to plasma. To explore this question, we adapt a coupled rate-equations model established for atomic ultracold plasmas to describe the energy-grained avalanche of electron-Rydberg and electron-ion collisions in our system. Adding channels of Rydberg predissociation and two-body, electron-cation dissociative recombination to the atomic formalism, we investigate the kinetics by which this relaxation distributes particle density and energy over Rydberg states, free electrons and neutral fragments. The results of this investigation suggest some mechanisms by which molecular fragmentation channels can affect the state of the plasma.

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Section: Resultsmentioning

confidence: 99%

“…We have adopted a supersonic beam strategy to form an ultracold plasma of nitric oxide molecular cations and electrons [6,7]. In these experiments, we use doubleresonant laser excitation of nitric oxide, cooled to 1 K in a seeded supersonic molecular beam, to produce a Rydberg gas of ≈ 10 12 molecules cm −3 in a single selected state.…”

Section: Introductionmentioning

confidence: 99%

On the formation and decay of a molecular ultracold plasma

Saquet

Morrison

Schulz-Weiling

et al. 2011

J. Phys. B: At. Mol. Opt. Phys.

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show abstract

“…This makes them an excellent platform for studying a wide range of plasma phenomena, such as equilibration of strongly coupled plasmas, [3][4][5][6][7][8][9][10][11][12][13][14] ambipolar diffusion with 15 and without 16,17 a magnetic field, electron plasma oscillations, 16,18 Tonks-Dattner resonances 19 and edge modes, 20 ion acoustic waves, 21 an electron drift instability, 22 threebody recombination at ultracold temperatures, 13,[23][24][25][26][27][28][29] and the crossover to an ultracold plasma from a dense gas of Rydberg atoms. [30][31][32][33] Recent experiments creating ultracold plasmas in a seeded supersonic molecular beam 34 introduce molecular processes to the plasma evolution and show promise for yielding more strongly coupled systems. Here, we take advantage of the ability to control the initial density distribution to create and study localized density perturbations, or ion holes, in an UNP in the hydrodynamic regime.…”

Section: Introductionmentioning

confidence: 99%

Ion holes in the hydrodynamic regime in ultracold neutral plasmas

et al. 2013

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We describe the creation of localized density perturbations, or ion holes, in an ultracold neutral plasma in the hydrodynamic regime, and show that the holes propagate at the local ion acoustic wave speed. We also observe the process of hole splitting, which results from the formation of a density depletion initially at rest in the plasma. One-dimensional, two-fluid hydrodynamic simulations describe the results well. Measurements of the ion velocity distribution also show the effects of the ion hole and confirm the hydrodynamic conditions in the plasma. V C 2013 AIP Publishing LLC.

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“…In the most recent time, similar systems began to be studied also by gas-dynamic cryogenic installations [7]. Besides, creation of the same plasma states by artificial release of gaseous clouds from spacecraft was discussed long time ago [8,9].…”

Section: Introductionmentioning

confidence: 99%

Characteristic features of temperature evolution in ultracold plasmas

Dumin

2011

Plasma Phys. Rep.

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A theoretical interpretation of the recent experimental studies of temperature evolution in the course of time in the freely-expanding ultracold plasma bunches, released from a magneto-optical trap, is discussed. The most interesting result is finding the asymptotics of the form T e ∝ t −(1.2±0.1) instead of t −2 , which was expected for the rarefied monatomic gas during inertial expansion. As follows from our consideration, the substantially decelerated decay of the temperature can be well explained by the specific features of the equation of state for the ultracold plasmas with strong Coulomb's coupling, whereas a heat release due to inelastic processes (in particular, three-body recombination) does not play an appreciable role in the first approximation. This conclusion is confirmed both by approximate analytical estimates, based on the model of "virialization" of the chargedparticle energies, and by the results of ab initio numerical simulation. Moreover, the simulation shows that the above-mentioned law of temperature evolution is approached very quickly-when the virial criterion is satisfied only within a factor on the order of unity.

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Evolution from a Molecular Rydberg Gas to an Ultracold Plasma in a Seeded Supersonic Expansion of NO

Cited by 98 publications

References 21 publications

On the formation and decay of a molecular ultracold plasma

On the formation and decay of a molecular ultracold plasma

Ion holes in the hydrodynamic regime in ultracold neutral plasmas

Characteristic features of temperature evolution in ultracold plasmas

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