Expansion of Ultracold Neutral Plasmas with Exponentially Decaying Density Distributions

Abstract

We present a study of the expansion of an ultracold neutral plasma (UCNP) with an initial density distribution that decays exponentially in space, created by photoionizing atoms shortly after their release from a quadrupole (or biconic cusp) magnetic trap. A characteristic ion acoustic timescale is evident in the evolution of the plasma size and velocity, indicating the dynamics are reasonably well described by a model of hydrodynamic expansion of a quasi-neutral plasma. However, for low plasma density and high initial electron temperature, excess ion kinetic energy in the vicinity of the central density peak suggests significant local non-neutrality at early times. Observations are compared to the well-understood self-similar expansion of an UCNP with an initial Gaussian density distribution, and a similar scaling law describes the evolution of plasma size for both cases.

arXiv comment7 pages, 7 figures

References in corpus (24)

• Creation of an Ultracold Neutral Plasma
• Plasma Oscillations and Expansion of an Ultracold Neutral Plasma
• Using Absorption Imaging to Study Ion Dynamics in an Ultracold Neutral Plasma
• Kinetic modelling and molecular dynamics simulation of ultracold neutral plasmas including ionic correlations
• Evolution from a molecular Rydberg gas to an ultracold plasma in a seeded supersonic expansion of NO
• Evolution of Ultracold, Neutral Plasmas
• Magnetic trapping of metastable ${}^3{P}_2$ atomic strontium
• Ion Acoustic Waves in Ultracold Neutral Plasmas
• Experimental Realization of an Exact Solution to the Vlasov Equations for an Expanding Plasma
• Bright focused ion beam sources based on laser-cooled atoms
• Electron Temperature Evolution in Expanding Ultracold Neutral Plasmas
• Relaxation to non-equilibrium in expanding ultracold neutral plasmas
• Velocity Relaxation in a Strongly Coupled Plasma
• Experimental measurement of non-Markovian dynamics and self-diffusion in a strongly coupled plasma
• Observation of an ultracold plasma instability
• The limit of strong ion coupling due to electron shielding
• Compact ultracold electron source based on a grating magneto optical trap
• Ion Temperature Evolution in an Ultracold Neutral Plasma
• Collisional and Radiative Processes in Optically Thin Plasmas
• Arrested relaxation in an isolated molecular ultracold plasma
• Charged State of a Spherical Plasma in Vacuum
• Emergence of Kinetic Behavior in Streaming Ultracold Neutral Plasmas
• Energy spread of ultracold electron bunches extracted from a laser cooled gas
• Combined molecular dynamics and quantum trajectories simulation of laser-driven, collisional systems