Ultrafast optical-field-induced photoelectron emission in a vacuum nanoscale gap: An exact analytical formulation

2021 ◽  
Vol 119 (19) ◽  
pp. 194101
Author(s):  
Yi Luo ◽  
Peng Zhang
2019 ◽  
Vol 5 (9) ◽  
pp. eaax4545 ◽  
Author(s):  
Chaojie Zhang ◽  
Chen-Kang Huang ◽  
Ken A. Marsh ◽  
Chris E. Clayton ◽  
Warren B. Mori ◽  
...  

Kinetic instabilities arising from anisotropic electron velocity distributions are ubiquitous in ionospheric, cosmic, and terrestrial plasmas, yet there are only a handful of experiments that purport to validate their theory. It is known that optical field ionization of atoms using ultrashort laser pulses can generate plasmas with known anisotropic electron velocity distributions. Here, we show that following the ionization but before collisions thermalize the electrons, the plasma undergoes two-stream, filamentation, and Weibel instabilities that isotropize the electron distributions. The polarization-dependent frequency and growth rates of these kinetic instabilities, measured using Thomson scattering of a probe laser, agree well with the kinetic theory and simulations. Thus, we have demonstrated an easily deployable laboratory platform for studying kinetic instabilities in plasmas.


2020 ◽  
Vol 8 (20) ◽  
pp. 6832-6838 ◽  
Author(s):  
Da Teng ◽  
Kai Wang ◽  
Qiongsha Huan ◽  
Weiguang Chen ◽  
Zhe Li

Tunable ultra-deep subwavelength optical field confinement is reported by using a graphene-coated nanowire-loaded silicon nano-rib waveguide.


Author(s):  
Neander Berto Mendes ◽  
Lineu José Pedroso ◽  
Paulo Marcelo Vieira Ribeiro

ABSTRACT: This work presents the dynamic response of a lock subjected to the horizontal S0E component of the El Centro earthquake for empty and completely filled water chamber cases, by coupled fluid-structure analysis. Initially, the lock was studied by approximation, considering it similar to the case of a double piston coupled to a two-dimensional acoustic cavity (tank), representing a simplified analytical model of the fluid-structure problem. This analytical formulation can be compared with numerical results, in order to qualify the responses of the ultimate problem to be investigated. In all the analyses performed, modeling and numerical simulations were done using the finite element method (FEM), supported by the commercial software ANSYS.


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