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Not long after metastable xenon was photoionized in a magneto-optical trap, groups in Europe and North America found that similar states of ionized gas evolved spontaneously from state-selected, high principal quantum number Rydberg gases.…
An ultra-cold molecular plasma with extraordinarily long lifetime (~0.5 ms) is generated under strong collisional cooling conditions in the expansion region of a seeded supersonic jet expansion close to the nozzle. A resonant two-photon…
In plasmas at very low temperatures formation of neutral atoms is dominated by collisional three-body recombination, owing to the strong ~ T^(-9/2) scaling of the corresponding recombination rate with the electron temperature T. While this…
We report a systematic experimental and numerical study of the expansion of ultra-cold Rydberg plasmas. Specifically, we have measured the asymptotic expansion velocities, $v_0$, of ultra-cold neutral plasmas (UNPs) which evolve from cold,…
Electrons in an expanding ultracold plasma are expected to be in quasi-equilibrium, since the collision times are short compared to the plasma lifetime, yet we observe electrons evaporating out as the ion density decreases during expansion.…
We present the first large-scale simulations of an ultracold, neutral plasma, produced by photoionization of laser-cooled xenon atoms, from creation to initial expansion, using classical molecular dynamics methods with open boundary…
We present a theoretical interpretation of the recently revealed features of temperature evolution in the ultracold plasma clouds released from a magneto-optical trap, namely: (a) its independence at the sufficiently large times on the…
An ellipsoidal volume of Rydberg molecules, entrained in a supersonic molecular beam, evolves on a nanosecond timescale to form a strongly coupled ultracold plasma. We present coupled rate-equation simulations that model the underlying…
We present the first observation of an instability in an expanding ultracold plasma. We observe periodic emission of electrons from an ultracold plasma in weak, crossed magnetic and electric fields, and a strongly perturbed electron density…
A long life-time (>0.3 ms) strongly-coupled molecular Rydberg plasma is generated by the excitation of nitric oxide into the high-n Rydberg threshold region in the high-density region of a supersonic jet expansion. After 310 \mus the plasma…
We develop a projection imaging technique to study ultracold plasma dynamics. We image the charged particle spatial distributions by extraction with a high-voltage pulse onto a position-sensitive detector. Measuring the 2D width of the ion…
When ultracold plasma is generated using photonization of laser cooled atoms, some atoms reach only upto Rydberg states. These in turn interact with the free electrons of the plasma and get ionized further. We study the interaction of…
We have performed a systematic study of the Bremsstrahlung emission from the electrons in the plasma of a commercial 14.5 GHz Electron-Cyclotron Resonance Ion Source. The electronic spectral temperature and the product of ionic and…
We report on the self-induced electron trapping occurring in a ultracold neutral plasma that is set to expand freely. At the early stages of the plasma, the ions are not thermalized follow a Gaussian spatial profile, providing the trapping…
Charge separation effects in the expansion of magnetized relativistic electron-ion plasmas into a vacuum are examined using 2-1/2-dimensional particle-in-cell plasma simulations. The electrostatic field at the plasma surface decelerates…
Three-body recombination, an important collisional process in plasmas, increases dramatically at low electron temperatures, with an accepted scaling of T_e^-9/2. We measure three-body recombination in an ultracold neutral xenon plasma by…
Several mechanisms by which an external electromagnetic field influences the temperature of a plasma are studied analytically and specialized to the system of an ultracold plasma (UCP) driven by a uniform radio frequency (RF) field. Heating…
Ultracold plasmas (UCPs) are created under conditions of near but not perfect neutrality. In the limit of zero electron temperature, electron screening results in non-neutrality manifesting itself as an interior region of the UCP with both…
Starting from the beginning of their research in the early 2000's, the ultracold plasmas were considered as a promising tool to achieve considerable values of the Coulomb coupling parameter for electrons. Unfortunately, this was found to be…
Absorption imaging and spectroscopy can probe the dynamics of an ultracold neutral plasma during the first few microseconds after its creation. Quantitative analysis of the data, however, is complicated by the inhomogeneous density…