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Schlagwörter:
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MPIPKS:
Light-matter interaction
Zusammenfassung:
The Yukawa one-component plasma (OCP) model is a paradigm for describing
plasmas that contain one component of interest and one or more other
components that can be treated as a neutralizing, screening background.
In appropriately scaled units, interactions are characterized entirely
by a screening parameter, kappa. As a result, systems of similar kappa
show the same dynamics, regardless of the underlying parameters (e.g.,
density and temperature). We demonstrate this behavior using ultracold
neutral plasmas (UNPs) created by photoionizing a cold (T <= 10 mK) gas.
The ions in UNP systems are well described by the Yukawa model, with the
electrons providing the screening. Creation of the plasma through
photoionization can be thought of as a rapid quench of the interaction
potential from kappa = infinity to a final kappa value set by the
electron density and temperature. We demonstrate experimentally that the
postquench dynamics are universal in. over a factor of 30 in density and
an order of magnitude in temperature. Results are compared with
molecular-dynamics simulations. We also demonstrate that features of the
postquench kinetic energy evolution, such as disorder-induced heating
and kinetic-energy oscillations, can be used to determine the plasma
density and the electron temperature.
