Transition to superdiffusive transport in turbulent plasmas.

We investigate the motion of charged particles in a turbulent electrostatic potential using guiding-center theory. By increasing the Larmor radius, the dynamics exhibit close-to-ballistic transport properties. The transition from diffusive to ballistic transport is analyzed using nonlinear dynamics.

Human septins organize as octamer-based filaments and mediate actin-membrane anchoring in cells.

Septins are cytoskeletal proteins conserved from algae and protists to mammals. A unique feature of septins is their presence as heteromeric complexes that polymerize into filaments in solution and on lipid membranes. Although animal septins associate extensively with actin-based structures in cells, whether septins organize as filaments in cells and if septin organization impacts septin function is not known.

Nonadiabatic effects in the double ionization of atoms driven by a circularly polarized laser pulse.

We study the double ionization of atoms subjected to circularly polarized (CP) laser pulses. We analyze two fundamental ionization processes: the sequential (SDI) and nonsequential (NSDI) double ionization in the light of the rotating frame (RF) which naturally embeds nonadiabatic effects in CP pulses. We use and compare two adiabatic approximations: The adiabatic approximation in the laboratory frame (LF) and the adiabatic approximation in the RF.

Envelope-Driven Recollisions Triggered by an Elliptically Polarized Pulse.

Increasing ellipticity usually suppresses the recollision probability drastically. In contrast, we report on a recollision channel with large return energy and a substantial probability, regardless of the ellipticity. The laser envelope plays a dominant role in the energy gained by the electron, and in the conditions under which the electron comes back to the core.

Capturing Photoelectron Motion with Guiding Centers.

Electron motion in combined strong laser and Coulomb fields is central to laser-matter interactions. By mapping this problem onto the motion of a guiding center, we derive a reduced model which naturally embeds important Coulomb effects such as focusing and asymmetry, and clearly distinguishes direct versus rescattered electron ionization processes. We demonstrate the power of this tool by unraveling the bifurcation in photoelectron momentum distributions seen in experiments.