Modeling terahertz emission from the target rear side during intense laser-solid interactions

2019 ◽  
Vol 100 (5) ◽  
Author(s):  
A. Woldegeorgis ◽  
S. Herzer ◽  
M. Almassarani ◽  
S. Marathapalli ◽  
A. Gopal
Keyword(s):  
Intense Laser ◽  
Rear Side ◽  
Terahertz Emission ◽  
Laser Solid Interactions

scholarly journals Measurement of the angle, temperature and flux of fast electrons emitted from intense laser–solid interactions

2015 ◽  
Vol 81 (5) ◽  
Author(s):  
D. R. Rusby ◽  
L. A. Wilson ◽  
R. J. Gray ◽  
R. J. Dance ◽  
N. M. H. Butler ◽  
...  
Keyword(s):  
High Intensity ◽  
Rear Surface ◽  
High Energy ◽  
Intense Laser ◽  
Rear Side ◽  
Measured Signal ◽  
X Rays ◽  
High Intensity Laser ◽  
Intensity Laser ◽  
Laser Solid Interactions

High-intensity laser–solid interactions generate relativistic electrons, as well as high-energy (multi-MeV) ions and x-rays. The directionality, spectra and total number of electrons that escape a target-foil is dependent on the absorption, transport and rear-side sheath conditions. Measuring the electrons escaping the target will aid in improving our understanding of these absorption processes and the rear-surface sheath fields that retard the escaping electrons and accelerate ions via the target normal sheath acceleration (TNSA) mechanism. A comprehensive Geant4 study was performed to help analyse measurements made with a wrap-around diagnostic that surrounds the target and uses differential filtering with a FUJI-film image plate detector. The contribution of secondary sources such as x-rays and protons to the measured signal have been taken into account to aid in the retrieval of the electron signal. Angular and spectral data from a high-intensity laser–solid interaction are presented and accompanied by simulations. The total number of emitted electrons has been measured as $2.6\times 10^{13}$ with an estimated total energy of $12\pm 1~\text{J}$ from a $100~{\rm\mu}\text{m}$ Cu target with 140 J of incident laser energy during a $4\times 10^{20}~\text{W}~\text{cm}^{-2}$ interaction.

Electron acceleration in intense laser-solid interactions at parallel incidence

2021 ◽  
Vol 51 (9) ◽  
pp. 833-837
Author(s):  
X Shen ◽  
Alexander M Pukhov ◽  
S E Perevalov ◽  
A A Solov'ev
Keyword(s):  
Electron Acceleration ◽  
Intense Laser ◽  
Laser Solid Interactions

scholarly journals Bremsstrahlung emission profile from intense laser-solid interactions as a function of laser focal spot size

2019 ◽  
Vol 61 (3) ◽  
pp. 034001 ◽  
Author(s):  
C D Armstrong ◽  
C M Brenner ◽  
E Zemaityte ◽  
G G Scott ◽  
D R Rusby ◽  
...  
Keyword(s):  
Focal Spot ◽  
Spot Size ◽  
Intense Laser ◽  
Focal Spot Size ◽  
Emission Profile ◽  
Bremsstrahlung Emission ◽  
Laser Focal Spot ◽  
Laser Solid Interactions

scholarly journals Escaping Electrons from Intense Laser-Solid Interactions as a Function of Laser Spot Size

2018 ◽  
Vol 167 ◽  
pp. 02001 ◽  
Author(s):  
Dean Rusby ◽  
Ross Gray ◽  
Nick Butler ◽  
Rachel Dance ◽  
Graeme Scott ◽  
...  
Keyword(s):  
Rear Surface ◽  
Spot Size ◽  
Intense Laser ◽  
Laser Spot Size ◽  
Particle In Cell ◽  
High Intensity Laser ◽  
Electric Potentials ◽  
Initial Interaction ◽  
Intensity Laser ◽  
Laser Solid Interactions

The interaction of a high-intensity laser with a solid target produces an energetic distribution of electrons that pass into the target. These electrons reach the rear surface of the target creating strong electric potentials that act to restrict the further escape of additional electrons. The measurement of the angle, flux and spectra of the electrons that do escape gives insights to the initial interaction. Here, the escaping electrons have been measured using a differentially filtered image plate stack, from interactions with intensities from mid 1020-1017 W/cm2, where the intensity has been reduced by defocussing to increase the size of the focal spot. An increase in electron flux is initially observed as the intensity is reduced from 4x1020 to 6x1018 W/cm2. The temperature of the electron distribution is also measured and found to be relatively constant. 2D particle-in-cell modelling is used to demonstrate the importance of pre-plasma conditions in understanding these observations.

scholarly journals High resolution bremsstrahlung and fast electron characterization in ultrafast intense laser–solid interactions

2013 ◽  
Vol 15 (12) ◽  
pp. 123038 ◽  
Author(s):  
C Zulick ◽  
B Hou ◽  
F Dollar ◽  
A Maksimchuk ◽  
J Nees ◽  
...  
Keyword(s):  
High Resolution ◽  
Fast Electron ◽  
Intense Laser ◽  
Laser Solid Interactions

scholarly journals Particle-in-cell simulations of laser–plasma interactions at solid densities and relativistic intensities: the role of atomic processes

2018 ◽  
Vol 6 ◽  
Author(s):  
D. Wu ◽  
X. T. He ◽  
W. Yu ◽  
S. Fritzsche
Keyword(s):  
Electromagnetic Fields ◽  
Ohmic Heating ◽  
Intense Laser ◽  
Bremsstrahlung Radiation ◽  
Simulation Code ◽  
Energetic Electrons ◽  
Particle In Cell ◽  
Laser Plasma Interactions ◽  
Collisional Damping ◽  
Laser Solid Interactions

Direct numerical simulation of intense laser–solid interactions is still of great challenges, because of the many coupled atomic and plasma processes, such as ionization dynamics, collision among charged particles and collective electromagnetic fields, to name just a few. Here, we develop a new particle-in-cell (PIC) simulation code, which enables us to calculate laser–solid interactions in a more realistic way. This code is able to cover almost ‘all’ the coupled physical processes. As an application of the new code, the generation and transport of energetic electrons in front of and within the solid target when irradiated by intense laser beams are studied. For the considered case, in which laser intensity is $10^{20}~\text{W}\cdot \text{cm}^{-2}$ and pre-plasma scale length in front of the solid is $10~\unicode[STIX]{x03BC}\text{m}$, several quantitative conclusions are drawn: (i) the collisional damping (although it is very weak) can significantly affect the energetic electrons generation in front of the target, (ii) the Bremsstrahlung radiation will be enhanced by 2–3 times when the solid is dramatically heated and ionized, (iii) the ‘cut-off’ electron energy is lowered by an amount of 25% when both collision damping and Bremsstrahlung radiations are included, and (iv) the resistive electromagnetic fields due to Ohmic heating play nonignorable roles and must be taken into account in such interactions.

scholarly journals Generation and transport of fast electrons inside cone targets irradiated by intense laser pulses

2006 ◽  
Vol 24 (1) ◽  
pp. 5-8 ◽  
Author(s):  
TATSUFUMI NAKAMURA ◽  
HITOSHI SAKAGAMI ◽  
TOMOYUKI JOHZAKI ◽  
HIDEO NAGATOMO ◽  
KUNIOKI MIMA
Keyword(s):  
Laser Pulses ◽  
Transport Processes ◽  
Hot Electrons ◽  
Intense Laser ◽  
Rear Side ◽  
Fast Electrons ◽  
Surface Magnetic Field ◽  
Particle In Cell ◽  
Intense Laser Pulses ◽  
Cone Target

Fast electrons are effectively generated from solid targets of cone-geometry by irradiating intense laser pulses, which is applied to fast ignition scheme. For realizing optimal core heating by those electrons, understanding the characteristics of electrons emitted from cone targets is crucial. In this paper, in order to understand the generation and transport processes of hot electrons inside the cone target, two-dimensional (2D) particle-in-cell (PIC) simulations were carried out. It is shown that hot electrons form current layers which are guided by self-generated surface magnetic field, which results in effective energy transfer from laser pulse to hot electrons. When the hot electrons propagate through the steep density gradient at the cone tip, electrostatic field is induced via Weibel instability. As a result, hot electrons are confined inside and emitted gradually from the target, as an electron beam of long duration. Energy spectrum and temporal profile of hot electrons are also evaluated at the rear side of the target, where the profile of rear side plasma is taken from the fluid code and the result is sent to Fokker-Planck code.

scholarly journals Hot electron refluxing in the short intense laser pulse interactions with solid targets and its influence on K-α radiation

Nukleonika ◽  
2015 ◽  
Vol 60 (2) ◽  
pp. 233-237 ◽  
Author(s):  
Vojtěch Horný ◽  
Ondřej Klimo
Keyword(s):  
Strong Electric Field ◽  
Target Material ◽  
Target Thickness ◽  
Intense Laser ◽  
Rear Side ◽  
Hot Electron ◽  
Fast Electrons ◽  
X Ray ◽  
Particle In Cell ◽  
Beam Interaction

Abstract Fast electrons created as a result of the laser beam interaction with a solid target penetrate into the target material and initialize processes leading to the generation of the characteristic X-ray K-α radiation. Due to the strong electric field induced at the rear side of a thin target the transmitted electrons are redirected back into the target. These refluxing electrons increase the K-α radiation yield, as well as the duration of the X-ray pulse and the size of the radiation emitting area. A model describing the electron refluxing was verified via particle-in-cell simulations for non-relativistic electron energies. Using this model it was confirmed that the effect of the electron refluxing on the generated X-ray radiation depends on the target thickness and the target material. A considarable increase of the number of the emitted K-α photons is observed especially for thin targets made of low-Z materials, and for higher hot electron temperatures.

Sign in / Sign up

Export Citation Format

Share Document