Attosecond Plasma Wave Dynamics in Laser-Driven Cluster Nanoplasmas

Abstract

We introduce a microscopic particle-in-cell approach that allows bridging the microscopic and macroscopic realms of laser-driven plasma physics. As a first application, resonantly driven cluster nanoplasmas are investigated. Our analysis reveals an attosecond plasma-wave dynamics in clusters with radii R is approximately equal to 30 nm. The plasma waves are excited by electrons recolliding with the cluster surface and travel toward the center, where they collide and break. In this process, energetic electron hot spots are generated along with highly localized attosecond electric field fluctuations, whose intensity exceeds the driving laser by more than 2 orders of magnitude. The ionization enhancement resulting from both effects generates a strongly nonuniform ion charge distribution. The observed nonlinear plasma-wave phenomena have a profound effect on the ionization dynamics of nanoparticles and offer a route to extreme nanoplasmonic field enhancements.

Light wave driven electron dynamics in clusters

“…The key advantages of MicPIC over conventional PIC approaches are the atomistic resolution of the plasma dynamics (including the surface) as well as the capability to directly model strongly coupled plasmas. In particular, this method was used to explore lightwave-driven metal clusters and reveal the underlying electron dynamics with unprecedented detail [34,35]. The most important aspects of MicPIC and its use for the microscopic analysis of radiation processes in plasmas is discussed in the remaining of this chapter.…”

“…Recently, the microscopic particle-in-cell (MicPIC) method [34,35] was introduced to overcome the limitations of the current modeling tools by connecting MD and PIC in a two-level approach. In MicPIC, only long-range electromagnetic interactions are treated on a coarse-grained PIC level.…”

“…4.5) -where the nanoplasma response is no longer linear -electrons can undergo extreme collective motions [34,35]. In this nonlinear regime, insight into the internal dynamics can be gained by looking at the scattering spectrum.…”

“…The efficiency is defined as the absorbed and scattered energy normalized by the pulse fluence and geometrical cluster cross section. Reproduced from [34]. C (2012) by the American Physical Society.…”

“…material of [34]). For w pic = 1.15 x, which is used for simulations later on, the evaluation of weights only for grid points closer than 3.5 x from the center of the particle conserves 99.998% of the total particle charge.…”