Disorder-induced heating of ultracold neutral plasmas created from atoms in partially filled optical lattices

Murphy, D.; Sparkes, B. M.

doi:10.1103/physreve.94.021201

Cited by 9 publications

(9 citation statements)

References 31 publications

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“…The simulation model involved a cubic box with periodic boundary conditions in each of the three dimensions. Equal numbers of electrons and ions (10 4 particles of each species) were introduced at random positions, so as to avoid any initial spatial pre-correlation amongst the charged particles that would have a suppressing effect on DIH [7,23]. Each simulation was carried out with three different initial random configurations and the presented results are a mean of these independent runs.…”

Section: Simulation Modelmentioning

confidence: 99%

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Reduction of electron heating by magnetizing ultracold neutral plasma

Tiwari

2018

Physics of Plasmas

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Electron heating in an ultracold neutral plasma is modeled using classical molecular dynamics simulations in the presence of an externally applied magnetic field. A sufficiently strong magnetic field is found to reduce disorder induced heating and three body recombination heating of electrons by constraining electron motion, and therefore heating, to the single dimension aligned with the magnetic field. A strong and long-lasting temperature anisotropy develops, and the overall kinetic electron temperature is effectively reduced by a factor of three. These results suggest that experiments may increase the effective electron coupling strength using an applied magnetic field.

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Section: Simulation Modelmentioning

confidence: 99%

“…Previous and ongoing efforts to increase coupling strength largely focus on ions, including laser cooling [19,20], introducing initial spatial correlation using blockaded Rydberg gases [7] or Fermi gases [21]. or by trapping the gas in an optical lattice [22,23]. We focus on electrons because they are more easily magnetized than ions.…”

Section: Introductionmentioning

confidence: 99%

Reduction of electron heating by magnetizing ultracold neutral plasma

Tiwari

2018

Physics of Plasmas

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“…The amount of heating is directly related with the level of disorder (lack of correlations) and, the excitation of initially ordered states should greatly reduce these effects. Proposals to prepare such initially ordered states include taking advantage of the Rydberg blockade mechanism [52], or via the preordering of atoms in an partially filled optical lattice [53]. While the latter could also be employed in the present context, the former more simply means that an initial excitation where the interatomic distance is limited by the blockade mechanism would also suppress the effects associated with disorder induced heating.…”

Section: Experimental Considerations and Disorder Induced Heatingmentioning

confidence: 99%

Roton-induced trapping in strongly correlated Rydberg gases

et al. 2018

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Atoms excited into high-lying Rydberg states and under strong dipole-dipole interactions exhibit phenomena associated with highly correlated and complex systems. We perform first principles numerical simulations on the dynamics of such systems. The emergence of a roton minimum in the excitation spectrum, as expected in strongly correlated gases and accurately described by Feynman's theory of liquid helium, is shown to significantly inhibit particle transport, with a strong suppression of the diffusion coefficient, due to the emerging spatial order. We also demonstrate how the ability to temporally tune the interaction strength among Rydberg atoms can be used in order to overcome the effects of disorder induced heating, allowing the study of unprecedented highly coupled regimes.

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“…DIH occurs as a consequence of creating a plasma in a non-equilibrium state [42]; the excess potential energy in the system is rapidly converted into kinetic energy. Mitigating DIH requires a precorrelated state (prior to ionization) [41], and strong coupling between ions has been shown to be theoretically possible in degenerate Fermi gases [41], Rydberg-blockaded gases [62] and optical lattices [63], all of which require very low temperatures. We employ a novel paradigm for precorrelation: compressing gases to high pressures at room temperature, thereby reducing the burden of trapping and cooling to extremely low temperatures.…”

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confidence: 99%

Controllable non-ideal plasmas from photoionized compressed gases

2018

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Based on a suite of molecular dynamics simulations, we propose a strategy for producing non-ideal plasmas with controllable properties over a wide range of densities between those of ultracold neutral plasmas and those of solid-density plasmas. We simulated the formation of non-equilibrium plasmas from photoionized, cool gases that are spatially precorrelated through neutral-neutral interactions that are important at moderate-to-high pressures. A wide range of physical properties, including Coulomb collisional rates, partial pressures, screening strengths, continuum lowering, interspecies Coulomb coupling, electron degeneracy and ionization states, were characterized across more than an order of magnitude variation in the initial gas pressure. A wide range of plasma properties are also found to vary when the initial pressure of a precorrelated gas is varied. Thus, we propose that nonideal plasmas with tunable properties can be generated by photo-ionizing a dense, precorrelated gas. We find that the optimal initial density range for the gas is near a Kirkwood/Widom-Fisher line in the neutral-gas phase diagram. This strategy for generating non-ideal plasmas suggests experiments that have significant advantages over both ultracold and solid-density plasma experiments because the collisional, collective and recombination timescales can be tuned across many orders of magnitude, potentially allowing for a wider range of diagnostics. Moreover, the added costs of cooling ultracold plasmas and diagnosing dense matter with x-rays are eliminated. two-temperature variations (i.e., separate electron and ion temperatures). The desired method would allow for systematic control of plasma properties, including transport and relaxation, ionization-potential depression (IPD), the non-ideal multi-temperature equation of state (EOS), and screening involving strongly coupled electrons. Transport properties [43,44] and relaxation processes [45][46][47][48] are important to validate and model dense plasma experiments. The advent of XFEL [49-51] has renewed interest in IPD (a.k.a.'continuum lowering'), and dense plasma experiments have been used to validate different IPD models [52][53][54][55]. An accurate EOS is essential for examining plasma evolution on the hydrodynamic scale, such as the evolution of fluid instabilities in ICF experiments [56,57] or UCNP expansion into a vacuum [29]. Strongly coupled electrons, which are difficult to create at high densities because of degeneracy, have been of theoretical and experimental interest for several decades [21,22], including, more recently, for their role in the conductance of liquid-helium surfaces [23]. Finally, such an approach could also serve as a platform for measuring coupled electron-ion modes, which have been of recent interest in dense two-temperature plasmas [58]. In fact, isolated experiments at these intermediate densities have been performed successfully [59-61]; however, controllability and tunability of plasma properties were not the focus of those experiments. Here, we pr...

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Disorder-induced heating of ultracold neutral plasmas created from atoms in partially filled optical lattices

Cited by 9 publications

References 31 publications

Reduction of electron heating by magnetizing ultracold neutral plasma

Reduction of electron heating by magnetizing ultracold neutral plasma

Roton-induced trapping in strongly correlated Rydberg gases

Controllable non-ideal plasmas from photoionized compressed gases

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