scholarly journals NUMERICAL SIMULATION OF PLATEAU FORMATION BY AN ELECTRON BUNCH ON THE DISTRIBUTION OF AN ACCELERATING WAKEFIELD IN A PLASMA

2020 ◽  
pp. 47-49
Author(s):  
V.I. Maslov ◽  
R.T. Ovsiannikov ◽  
N. Delerue ◽  
V. Kubytskyi ◽  
I.P. Levchuk ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Electron Bunch ◽  
Plasma Accelerator ◽  
The Self ◽  
Promising Candidate ◽  
Particle In Cell ◽  
The Past ◽  
Self Consistent ◽  
Plasma Accelerators

Over the past decade the production of multi-gigaelectrons from laser-driven and electron-bunch-driven plasma accelerators has been successfully demonstrated. However, applications require improvements of accelerated bunch size and its energy spread. One promising candidate to satisfy these requirements is to externally inject an electron bunch into an electron-bunch-driven plasma accelerator. We present studies on the optimization of the self-consistent distribution of an accelerating wakefield of plateau type, which can lead to improvement of final quality of the externally injected and accelerated electron bunch, using simulations with the particle-in-cell code LCODE. We quantified the effect of the injected bunch density on the plateau formation in the blowout regime.

scholarly journals Attosecond betatron radiation pulse train

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Vojtěch Horný ◽  
Miroslav Krůs ◽  
Wenchao Yan ◽  
Tünde Fülöp
Keyword(s):  
Laser Pulse ◽  
Electron Bunch ◽  
Spatial Modulation ◽  
Diagnostic Tools ◽  
X Ray ◽  
Particle In Cell ◽  
Potential Applications ◽  
Order Of Magnitude ◽  
Wavelength Radiation ◽  
Plasma Accelerators

Abstract High-intensity X-ray sources are essential diagnostic tools for science, technology and medicine. Such X-ray sources can be produced in laser-plasma accelerators, where electrons emit short-wavelength radiation due to their betatron oscillations in the plasma wake of a laser pulse. Contemporary available betatron radiation X-ray sources can deliver a collimated X-ray pulse of duration on the order of several femtoseconds from a source size of the order of several micrometres. In this paper we demonstrate, through particle-in-cell simulations, that the temporal resolution of such a source can be enhanced by an order of magnitude by a spatial modulation of the emitting relativistic electron bunch. The modulation is achieved by the interaction of the that electron bunch with a co-propagating laser beam which results in the generation of a train of equidistant sub-femtosecond X-ray pulses. The distance between the single pulses of a train is tuned by the wavelength of the modulation laser pulse. The modelled experimental setup is achievable with current technologies. Potential applications include stroboscopic sampling of ultrafast fundamental processes.

scholarly journals Proposed scheme for compact GeV laser plasma accelerator

2006 ◽  
Vol 24 (2) ◽  
pp. 255-259 ◽  
Author(s):  
A.F. LIFSCHITZ ◽  
J. FAURE ◽  
Y. GLINEC ◽  
V. MALKA ◽  
P. MORA
Keyword(s):  
Laser Plasma ◽  
Electron Bunch ◽  
State Of The Art ◽  
Plasma Accelerator ◽  
Monoenergetic Electron ◽  
High Quality ◽  
Electron Bunches ◽  
Plasma Accelerators ◽  
Laser Plasma Accelerator ◽  
Low Density Plasma

The design of a two-stage compact GeV electron accelerator is presented. The accelerator is as follows: (1) an ultra-short electron bunch is produced in a state-of-the-art laser-plasma accelerator (injector stage), (2) it is injected into an accelerating stage consisting of a centimeter length low density plasma interacting with a petawatt laser pulse. The parameters for the injector are taken from recent experimental results showing that high quality, ultra-short, and quasi-monoenergetic electron beams are now being produced in laser-plasma accelerators. Simulations performed with WAKE show that this method can lead to the production of high quality, monoenergetic, and sub-50 fs electron bunches at the GeV energy level.

Parallel 3-D particle-in-cell modelling of charged ultrarelativistic beam dynamics

2015 ◽  
Vol 81 (6) ◽  
Author(s):  
Marina A. Boronina ◽  
Vitaly A. Vshivkov
Keyword(s):  
Distribution Function ◽  
Electromagnetic Fields ◽  
High Efficiency ◽  
Three Dimensional ◽  
The Self ◽  
Beam Dynamics ◽  
Particle In Cell ◽  
Self Consistent ◽  
Longitudinal Effects ◽  
Parallel Code

We present a three-dimensional (3-D) particle-in-cell (PIC) model and parallel code for the self-consistent motion of charged ultrarelativistic beams (${\it\gamma}\sim 10^{3}{-}10^{5}$) in supercolliders. We use the 3-D set of Maxwell’s equations for the electromagnetic fields, and the Vlasov equation for the distribution function of the beam particles. The model incorporates automatically the longitudinal effects, which can play a significant role in the cases of super-high densities. We present numerical results for the dynamics of two focused ultrarelativistic beams with a size ratio 10:1:100. The results demonstrate high efficiency of the proposed computational methods and algorithms, which are applicable to a variety of problems in relativistic plasma physics.

Numerical Simulation and Experiment of Self-Piercing Riveting with Solid Rivet Joining Multi-Layer Aluminum Sheets

2009 ◽  
Vol 628-629 ◽  
pp. 641-646 ◽  
Author(s):  
Zhi Chao Huang ◽  
Qiu Hua Yao ◽  
Ning Jiang ◽  
Ze Jie Zhou
Keyword(s):  
Numerical Simulation ◽  
Transition Point ◽  
Maximum Stress ◽  
Sheet Thickness ◽  
The Self ◽  
Forming Process ◽  
Aluminum Sheets ◽  
Simulation And Experiment ◽  
Distribution Of Stress

Numerical simulation and experiment of self-piercing riveting with solid rivet joining multi-layer aluminum sheets are carried out in this paper. The forming process of the riveting and the distribution of stress are analyzed, the results show that the simulation is consistent with the experiment. The results of experiment prove that the transition point of the cone-shaped head of the solid rivet, the size and position of groove affect directly the quality of riveting. The fillet at the transition point of the cone-shaped head of the solid rivet can decline the maximum stress of the rivet. When the distance between the center of groove and bottom of rivet is about three quarters of the bottom sheet thickness, the bottom sheet of self-piercing does not fall off. The self-piercing riveting with solid rivet joining multi-layer aluminum sheets is feasible.

Investigation on Hole Punching Process with Combined Punch to Improve Surface Quality during the Materials Forming Process

2017 ◽  
Vol 737 ◽  
pp. 77-82
Author(s):  
Pan Pan Yao ◽  
Qiang Wang
Keyword(s):  
Numerical Simulation ◽  
Surface Quality ◽  
Hydraulic Press ◽  
Simulation Software ◽  
The Self ◽  
Improve Quality ◽  
Forming Process ◽  
Medium Thickness ◽  
Punching Process

The present work shows the viability of a combined punch that makes possible to perform a hole punching followed by a hole burnishing in only one operation. The advantage of this combined punch is forming processes in only one process on medium thickness plate. In this work were tested two different configurations of punches which one of them is the conventional punch and another is a new structure of combined punch. The new structure of combined punch is added the step and inclined edge at the cutting edge on the basis of conventional punch. They are made of the same materials that are Cr12MoV. The new structure of combined punch and the conventional punch are studied by using numerical simulation and experimental research in this paper. During the materials forming process of hole punching, the simulation software ANSYS is used to simulate. The YZ32-100 Hydraulic press with nominal and the self-made die sets and the thick of 16mm Q235 sheet metal is selected in this experiment. The analysis of the obtained results showed that the hole surface quality of combined punch is superior to the conventional punch. It is prove that the new structure of combined punch can improve quality of punching.

Immunoferritin localization of intracellular antigens in positively stained frozen sections

1978 ◽  
Vol 36 (2) ◽  
pp. 168-169
Author(s):  
K. T. Tokuyasu
Keyword(s):  
Surface Tension ◽  
Water Surface ◽  
Thin Layers ◽  
The Other ◽  
Positive Staining ◽  
Frozen Sections ◽  
The Past ◽  
Ultrathin Frozen Sections ◽  
Definition Of

During the past investigations of immunoferritin localization of intracellular antigens in ultrathin frozen sections, we found that the degree of negative staining required to delineate u1trastructural details was often too dense for the recognition of ferritin particles. The quality of positive staining of ultrathin frozen sections, on the other hand, has generally been far inferior to that attainable in conventional plastic embedded sections, particularly in the definition of membranes. As we discussed before, a main cause of this difficulty seemed to be the vulnerability of frozen sections to the damaging effects of air-water surface tension at the time of drying of the sections.Indeed, we found that the quality of positive staining is greatly improved when positively stained frozen sections are protected against the effects of surface tension by embedding them in thin layers of mechanically stable materials at the time of drying (unpublished).

Self-Compassion and Quality of Life in Adults Who Stutter

2020 ◽  
Vol 29 (4) ◽  
pp. 2097-2108
Author(s):  
Robyn L. Croft ◽  
Courtney T. Byrd
Keyword(s):  
Quality Of Life ◽  
Social Connectedness ◽  
The Self ◽  
Future Research ◽  
Self Compassion ◽  
Adults Who Stutter ◽  
And Gender ◽  
Relationship Of ◽  
The Impact

Purpose The purpose of this study was to identify levels of self-compassion in adults who do and do not stutter and to determine whether self-compassion predicts the impact of stuttering on quality of life in adults who stutter. Method Participants included 140 adults who do and do not stutter matched for age and gender. All participants completed the Self-Compassion Scale. Adults who stutter also completed the Overall Assessment of the Speaker's Experience of Stuttering. Data were analyzed for self-compassion differences between and within adults who do and do not stutter and to predict self-compassion on quality of life in adults who stutter. Results Adults who do and do not stutter exhibited no significant differences in total self-compassion, regardless of participant gender. A simple linear regression of the total self-compassion score and total Overall Assessment of the Speaker's Experience of Stuttering score showed a significant, negative linear relationship of self-compassion predicting the impact of stuttering on quality of life. Conclusions Data suggest that higher levels of self-kindness, mindfulness, and social connectedness (i.e., self-compassion) are related to reduced negative reactions to stuttering, an increased participation in daily communication situations, and an improved overall quality of life. Future research should replicate current findings and identify moderators of the self-compassion–quality of life relationship.

Sign in / Sign up

Export Citation Format

Share Document