Nonequilibrium evolution of strong-field anisotropic ionized electrons towards a delayed plasma-state

Pasenow, B.; Moloney, Jerome V.; Koch, S. W.; Chen, S. H.; Becker, Andreas

doi:10.1364/oe.20.002310

Cited by 12 publications

(20 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar agreement between the results of the two methods has been found at other laser parameters, for example, the asymmetry in the photoelectron momentum distributions in few-cycle pulses as a function of the carrier-envelope phase could be well reproduced (e.g., Ref. [40]). …”

Section: Comparison With Results Of Grid Calculationssupporting

confidence: 80%

Application of a numerical-basis-state method to strong-field excitation and ionization of hydrogen atoms

Chen

Gao

et al. 2012

Phys. Rev. A

View full text Add to dashboard Cite

We apply a numerical-basis-state method to study dynamical processes in the interaction of atoms with strong laser pulses. The method is based on the numerical representation of finite-space energy eigenstates of the field-free atomic Hamiltonian in a box on a grid and the expansion of the solution of the full time-dependent Schrödinger equation, including the interaction with the field, in this numerical basis. We apply the method to the hydrogen atom and present results for excitation and ionization probabilities as well as photoelectron momentum distributions. Convergence of the results with respect to the size of the basis as well as the parallel efficiency of the numerical algorithm is studied. The results of the numerical-basis-state method are in good agreement with those of two-dimensional numerical grid calculations. The computation times for the numerical-basis-state method usually are found to be significantly smaller than those for the two-dimensional grid calculations, whereas, even higher excited states can be well represented. We further apply this method to study a few recently reported phenomena related to strong-field excitation of atoms, such as the dependence of the excitation probabilities on the carrier-envelope phase in ultrashort pulses as well as the so-called frustrated ionization.

show abstract

Section: Comparison With Results Of Grid Calculationssupporting

confidence: 80%

Application of a numerical-basis-state method to strong-field excitation and ionization of hydrogen atoms

Chen

Gao

et al. 2012

Phys. Rev. A

View full text Add to dashboard Cite

show abstract

“…To treat the electron Coulomb dynamics, we use a Monte Carlo scheme [4]. Here, the distribution is represented as an ensemble of individual particles whose initial momenta are randomly created using the TDSE-calculated free-electron wavefunctions to generate the initial probability distribution.…”

Section: Numerical Solution and Resultsmentioning

confidence: 99%

“…In our previous investigations [4], we presented a microscopic analysis of the short-time dynamics of photoionized electrons created by an intense few-cycle laser pulse. After the USP, the photoionized free electrons are left in a highly anisotropic, nonequilibrium momentum distribution.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic terahertz response from a strong-field ionized electron-ion plasma

et al. 2013

Self Cite

View full text Add to dashboard Cite

A microscopic theory is adapted to compute the time-resolved terahertz (THz) probe response of a dynamically evolving, strong-field ionized electron-ion plasma. The numerical solutions show that the relaxation of the initially highly anisotropic carrier distributions leads to a polarization dependent short-time THz response. This THz polarization discrimination gradually vanishes as the plasma approaches a thermodynamic equilibrium configuration via electron-electron and electron-ion scattering. The detailed carrier-relaxation dynamics causes a strongly nonmonotonic time-development of the THz absorption.

show abstract

“…In Ref. [30], the BME was solved for an idealized gas of dilute hydrogen atoms excited by a femtosecond pulse and the subsequent time dynamics of the electronic system was monitored. The quantum calculations of the femtosecond laser-induced ionization yield highly anisotropic electron and ion angular (momentum) distributions on femtosecond timescales.…”

Section: Microscopic Approachmentioning

confidence: 99%

Memory effects in the long-wave infrared avalanche ionization of gases: a review of recent progress

et al. 2019

View full text Add to dashboard Cite

There are currently intense efforts being directed towards extending the range and energy of long distance nonlinear pulse propagation in the atmosphere by moving to longer infrared wavelengths, with the purpose of mitigating the effects of turbulence. In addition, picosecond and longer pulse durations are being used to increase the pulse energy. While both of these tacks promise improvements in applications, such as remote sensing and directed energy, they open up fundamental issues regarding the standard model used to calculate the nonlinear optical properties of dilute gases. Amongst these issues is that for longer wavelengths and longer pulse durations, exponential growth of the laser-generated electron density, the so-called avalanche ionization, can limit the propagation range via nonlinear absorption and plasma defocusing. It is therefore important for the continued development of the field to assess the theory and role of avalanche ionization in gases for longer wavelengths. Here, after an overview of the standard model, we present a microscopically motivated approach for the analysis of avalanche ionization in gases that extends beyond the standard model and we contend is key for deepening our understanding of long distance propagation at long infrared wavelengths. Our new approach involves the mean electron kinetic energy, the plasma temperature, and the free electron density as dynamic variables. The rate of avalanche ionization is shown to depend on the full time history of the pulsed excitation, as opposed to the standard model in which the rate is proportional to the instantaneous intensity. Furthermore, the new approach has the added benefit that it is no more computationally intensive than the standard one. The resulting memory effects and some of their measurable physical consequences are demonstrated for the example of long-wavelength infrared avalanche ionization and long distance high-intensity pulse propagation in air. Our hope is that this report in progress will stimulate further discussion that will elucidate the physics and simulation of avalanche ionization at long infrared wavelengths and advance the field. arXiv:1810.07345v2 [physics.optics]

show abstract

Nonequilibrium evolution of strong-field anisotropic ionized electrons towards a delayed plasma-state

Cited by 12 publications

References 13 publications

Application of a numerical-basis-state method to strong-field excitation and ionization of hydrogen atoms

Application of a numerical-basis-state method to strong-field excitation and ionization of hydrogen atoms

Anisotropic terahertz response from a strong-field ionized electron-ion plasma

Memory effects in the long-wave infrared avalanche ionization of gases: a review of recent progress

Contact Info

Product

Resources

About