Electron localization in strong coupling-influenced ultracold plasmas

Ultracold plasmas are interesting objects in part because for typical parameters they can exhibit strong coupling influenced behavior and also because they are comparatively straightforward to model using modern computational techniques. Using experimentally-validated molecular dynamics simulations of ultracold plasmas with significant electron strong coupling, we have found that electrons are commonly localized (classically) by ions to finite volumes of space for significant periods of time. This is through the expected Rydberg atom formation, but in addition less tightly bound configurations are common. Up to 10% or more of the electrons are noticeably localized in experimentally accessible ultracold plasma conditions soon after formation. As a result, many collision properties that can be extracted from the molecular dynamics simulations are no longer straightforward to obtain. The relationship between this localization and collision properties will be described, as will the general applicability to plasmas where strong coupling is relevant.