Very slow expansion of an ultracold plasma formed in a seeded supersonic molecular beam of NO

Morrison, J. P.; Rennick, Chris; Grant, Edward R.

doi:10.1103/physreva.79.062706

Cited by 29 publications

(41 citation statements)

References 33 publications

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“…In this experiment [16], the expansion of the plasma seems to be too slow for the expected electron temperature at their density. The density of their plasma is ∼10 3 × greater than previous ultracold neutral plasmas and they have molecular ions instead of atomic ions.…”

Section: Introductionmentioning

confidence: 72%

Early time properties of ultracold neutral plasmas

Niffenegger

Gilmore

Robicheaux

2011

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

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We present simulations of some of the early time properties of ultracold neutral plasmas. We focus on three aspects of this system. First, we study the earliest electron dynamics when the initial temperature of the electrons would place them in the strongly coupled regime. We focus on times out to ∼10 plasma periods of the electron but also present results out to ∼85 plasma periods. In particular, we study how the formation of Rydberg atoms leads to heating and how the mass of the ion could enter the dynamics. Second, we study how the ions behave when the electrons are at high temperatures by comparing simulations that treat the electrons as a fluid and simulations that simultaneously include the electrons and ions. For light ions, the electron-ion scattering transfers substantial energy from the electrons to the ions. Finally, we study the ion motion at early times and at low temperatures where the electron evolution and ion motion could be at comparable time scales. This allows a test of electron-ion scattering when the electron plasma is nearly strongly coupled and we find that the recent values for the electron-ion scattering rate underestimate the ion heating in our calculations.

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Section: Introductionmentioning

confidence: 72%

Early time properties of ultracold neutral plasmas

Niffenegger

Gilmore

Robicheaux

2011

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

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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%

“…The width of the molecular beam determines the long axis of this ellipsoid. The short axes conforms with the two-dimensional Gaussian intensity distribution of the spatially filtered ω 1 laser beam, collimated to a full-width at half-maximum of 758 µm [7]. The plasma produced in this volume travels with the velocity of the molecular beam over an adjustable distance to pass through the (x, y) vertical plane of the imaging grid, G 2 .…”

Section: Methodsmentioning

confidence: 99%

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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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“…Another experimental results for ultracold plasmas are obtained recently in [50,51]. The preliminary estimation for lifetime is 30 mks and for ion (electron) density is 5 · 10 12 cm −3 .…”

Section: Nonideality Effects: Rate Of Recombinationmentioning

confidence: 94%

Density and Nonideality Effects in Plasmas

Lankin

Norman

2009

Contrib. Plasma Phys.

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Self-consistent joint description of free and weakly bound electron states in plasmas is considered. Existence of two problems is emphasized: restriction of the number of atomic excited states and description of the smooth crossover from bound pair electron-ion excited states to collective excitations of free electrons. The spectrum domain intermediate between low-lying excited atoms and free electron continuous energy levels is studied. Density and nonideality effects are separated. The density effects are predominant for the shape of the curve of the energy spectrum near the ionization limit. It corresponds to the suppression of spectral lines in ideal multicharge plasma of warm dense matter. A suppression of collisional recombination turns out to be a nonideality effect. The suppression agrees with the measurements for ultracold plasmas and warm dense matter.

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Very slow expansion of an ultracold plasma formed in a seeded supersonic molecular beam of NO

Cited by 29 publications

References 33 publications

Early time properties of ultracold neutral plasmas

Early time properties of ultracold neutral plasmas

On the formation and decay of a molecular ultracold plasma

Density and Nonideality Effects in Plasmas

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