לוח שנה משולב

Rotating turbulence appears in atmospheric, geophysics and astrophysical sys-tems. Despite intensive study, many aspects of such flows remained unre-solved. Even the global framework which should be used for the description of rotating turbulence is a subject of an active debate. On the one hand the formalism of two-dimensional turbulence is useful in the description of many aspects of rotating turbulence. On the other hand, theoretical and numerical works suggest that the formalism of wave turbulence should provide a reliable description of the entire three-dimensional flow field. The waves that are suggested as basis for this turbulence are Coriolis driven inertial waves that are solutions of the linearized rotating Navier-Stokes equation.
In this talk I will present experimental evidences for the existence of inertial wave turbulence in deep steady rotating turbulence. First, we show that the energy spectrum evolves via energy cascade from small to large scales. Next we show that in both, evolving and steady state flows, the broad energy spectrum is concentrated along the dispersion relation of inertial waves. The turbulent fields are, therefore, well described as ensembles of 3D interacting inertial waves.

Tal Eizman

The interaction of intense light with atoms or molecules can lead to the generation of extreme ultraviolet (XUV) pulses and energetic electron pulses of attosecond (10-18) duration. The advent of attosecond technology opens up new fields of time-resolved studies in which transient electronic dynamics can be studied with a temporal resolution that was previously unattainable.
I will review the main challenges and goals in the field of attosecond science. As an example, I will focus on a recent experiment where the dynamics of tunnel ionization – one of the most fundamental strong-field phenomena – were studied. Specifically, we were able to measure the times when different electron trajectories exit from under the tunneling barrier created by a laser field and the atomic binding potential. In the following stage we resolved how the barrier thickness and tunneling probability, evolve within the optical cycle. Finally, subtle delays in ionization times from two orbitals in a molecular system were resolved. This experiment provides an additional, important step towards achieving the ability to resolve multielectron phenomena -- a long-term goal of attosecond studies.