scholarly journals Structuring Free-Standing Foils for Laser-Driven Particle Acceleration Experiments

2021 ◽  
Vol 9 ◽  
Author(s):  
Cristina C. Gheorghiu ◽  
Stefania C. Ionescu ◽  
Petru Ghenuche ◽  
Mihail O. Cernaianu ◽  
Domenico Doria ◽  
...  
Keyword(s):  
Particle Acceleration ◽  
Nuclear Physics ◽  
Target Surface ◽  
Energy Conversion Efficiency ◽  
Particle Energy ◽  
Free Standing ◽  
Thin Foils ◽  
Laser Systems ◽  
Nanostructured Gold ◽  
Target Design

The recent development of petawatt-class laser systems sets a focus on the development of ultra-thin free-standing targets to access enhanced particle acceleration schemes vital for future applications, such as, medical and laser-driven nuclear physics. Specific strategies are required to improve the laser-to-particle energy conversion efficiency and increase the maximum particle energy. One of the promising approaches is based on the target design optimization; either by tuning key parameters which will strongly affect the laser-matter interaction process (e.g., material, composition, density, thickness, lateral dimensions, and shape) or by using micro/nanostructures on the target surface. At ELI-NP, considerable efforts are dedicated to extend the target capabilities beyond simple planar target design and develop complex targets with tailored properties suitable for high-power laser-plasma interaction experiments, as well as for studies with gamma and positrons beams. The paper provides an overview of the manufacturing capabilities currently available within ELI-NP Targets Laboratory for providing users with certain types of solid targets, specifically micro/nanostructured gold and copper foils and microns thick, porous anodized alumina. Also, optimization studies of alternative patterns (micro/nanodots) on silicon substrate are presented for future implementation on metallic free-standing thin foils.

scholarly journals Review of ultrafast ion acceleration experiments in laser plasma at Max Born Institute

2007 ◽  
Vol 25 (3) ◽  
pp. 347-363 ◽  
Author(s):  
P.V. Nickles ◽  
S. Ter-Avetisyan ◽  
M. Schnürer ◽  
T. Sokollik ◽  
W. Sandner ◽  
...  
Keyword(s):  
Nuclear Physics ◽  
Experimental Studies ◽  
Emission Spectra ◽  
Relativistic Effects ◽  
Plasma Dynamics ◽  
Max Born ◽  
Recent Advances ◽  
Thin Foils ◽  
Laser Systems ◽  
Broad Variety

New perspectives have been opened up in the field of laser–matter interactions due to recent advances in laser technology, leading to laser systems of high contrast and extreme intensity values, where the frontier of maximum intensity is pushed now to about 1022 W/cm2. Many striking phenomena such as laser-acceleration of electrons up to the GeV level, fast moving ions with kinetic energies of several 10s of MeV, as well as nuclear physics experiments have already actuated a broad variety of theoretical as well as experimental studies. Also highly relativistic effects like laser induced electron-positron pair production are under discussion. All these activities have considerably stimulated the progress in understanding the underlying physical processes and possible applications. This article reviews recent advances in the experimental techniques as well as the associated plasma dynamics studies at relativistic intensities performed at the Max-Born-Institute (MBI). Interactions of a laser pulse at intensities above 1019 W/cm2 with water- and heavy-water droplets, as well as, with thin foils are discussed. Rear and front side acceleration mechanisms, particle dynamics inside the dense target, proton source characteristics, strong modulations in proton and deuteron emission spectra, and finally generation of quasi-monoenergetic deuteron bursts are the topics covered in the article.

scholarly journals Method development for producing thin 14C foils

2020 ◽  
Vol 229 ◽  
pp. 04002
Author(s):  
Matthew Gott ◽  
John Greene ◽  
Igor Pavlovsky ◽  
Richard Fink
Keyword(s):  
High Purity ◽  
Nuclear Physics ◽  
Method Development ◽  
Carbon Oxide ◽  
Carbon Powder ◽  
Robust Method ◽  
Purification Method ◽  
Physics Community ◽  
Thin Foils

Thin, isotopic 14C foils are of great interest to the nuclear physics community as neutron-rich targets. Historically, these foils have been extremely difficult to prepare and an effort is underway to make them readily available. The stock material of 14C available at Argonne contains a number of oxide impurities (SiO2, MgO, and Al2O3), which affect the composition and stability of the fabricated foil. A simple, robust method was developed (using natC as a surrogate) to purify the 14C material while minimizing loss and potential spread of the material. Thin foils were fabricated using the purified carbon, the unpurified carbon/oxide mix, and purchased high-purity carbon powder. SEM and EDS of the resulting foils was performed and the efficacy of this purification method was demonstrated.

scholarly journals Particle acceleration theory

2006 ◽  
Vol 2 (14) ◽  
pp. 99-100
Author(s):  
Roger D. Blandford
Keyword(s):  
Particle Acceleration ◽  
Electric Field ◽  
Particle Energy ◽  
Charge Particle ◽  
Efficient Conversion ◽  
Bulk Energy ◽  
Work Done

AbstractAstrophysical particle acceleration involves the efficient conversion of bulk energy to individual charge particle energy through work done by electric field. The ways in which this happens are quite varied but when considered from a physics perspective, commonalities can found between acceleration in quite different sites.

Direct measurement of the electron density driving the laser particle acceleration with thin foils

2008 ◽  
Author(s):  
O. Jackel ◽  
S. M. Pfotenhauer ◽  
J. Polz ◽  
H. P. Schlenvoigt ◽  
M. C. Kaluza ◽  
...  
Keyword(s):  
Particle Acceleration ◽  
Electron Density ◽  
Direct Measurement ◽  
Thin Foils

scholarly journals Particle acceleration in coalescent and squashed magnetic islands

2018 ◽  
Vol 620 ◽  
pp. A121 ◽  
Author(s):  
Q. Xia ◽  
V. Zharkova
Keyword(s):  
Particle Acceleration ◽  
Electric Field ◽  
Power Laws ◽  
Particle Energy ◽  
Energy Spectra ◽  
Magnetic Islands ◽  
Current Sheets ◽  
The Difference ◽  
Energy Gains ◽  
Electron Clouds

Aims. Magnetic reconnection in large Harris-type reconnecting current sheets (RCSs) with a single X-nullpoint often leads to the occurrence of magnetic islands with multiple O- and X-nullpoints. Over time these magnetic islands become squashed, or coalescent with two islands merging, as has been observed indirectly during coronal mass ejection and by in-situ observations in the heliosphere and magnetotail. These points emphasise the importance of understanding the basic energising processes of ambient particles dragged into current sheets with magnetic islands of different configuration. Methods. Trajectories of protons and electrons accelerated by a reconnection electric field are investigated using a test particle approach in RCSs with different 3D magnetic field topologies defined analytically for multiple X- and O-nullpoints. Trajectories, densities, and energy distributions are explored for 106 thermal particles dragged into the current sheets from different sides and distances. Results. This study confirms that protons and electrons accelerated in magnetic islands in the presence of a strong guiding field are ejected from a current sheet into the opposite semiplanes with respect to the midplane. Particles are found to escape O-nullpoints only through the neighbouring X-nullpoints along (not across) the midplane following the separation law for electrons and protons in a given magnetic topology. Particles gain energy either inside O-nullpoints or in the vicinity of X-nullpoints that often leads to electron clouds formed about the X-nullpoint between the O-nullpoints. Electrons are shown to be able to gain sub-relativistic energies in a single magnetic island. Energy spectra of accelerated particles are close to power laws with spectral indices varying from 1.1 to 2.4. The more squashed the islands the larger the difference between the energy gains by transit and bounced particles, which leads to their energy spectra having double maxima that gives rise to fast-growing turbulence. Conclusions. Particles are shown to gain the most energy in multiple X-nullpoints between O-nullpoints (or magnetic islands). This leads to the formation of electron clouds between magnetic islands. Particle energy gains are much larger in squashed islands than in coalescent ones. In summary, particle acceleration by a reconnection electric field in magnetic islands is much more effective than in an RCS with a single X-nullpoint.

scholarly journals Modeling of the electrostatic sheath shape on the rear target surface in short-pulse laser-driven proton acceleration

2006 ◽  
Vol 24 (1) ◽  
pp. 163-168 ◽  
Author(s):  
ERIK BRAMBRINK ◽  
MARKUS ROTH ◽  
ABEL BLAZEVIC ◽  
THEODOR SCHLEGEL
Keyword(s):  
Short Pulse ◽  
Target Surface ◽  
Laser Pulses ◽  
Target Thickness ◽  
Intense Laser ◽  
Rear Side ◽  
Proton Beams ◽  
Short Pulse Laser ◽  
Thin Foils ◽  
In The Beginning

Proton beams, generated in the interaction process of short ultra-intense laser pulses with thin foils, carry imprints of rear side target structures. These intensity patterns, imaged with a particle detector, sometimes show slight deformations. We propose an analytical model to describe these deformations by the spatial shape of a monoenergetic layer of protons in the beginning of free proton propagation. We also present results of simulations, which reproduce the detected structures and allow finally making quantitative conclusions on the shape of the layer. In experiments with electrically conducting targets, the shape is always close to a parabolic one independently on target thickness or laser parameters. Since the protons are pulled by the free electrons, there must be a strong correlation to the electron space charge distribution on the rear side of the illuminated foil. Simulations demonstrate that the deformations in the detected patterns of the proton layers are very sensitive to the initial layer shape. Analyzing spatial structures of the generated proton beams we can indirectly conclude on electron transport phenomena in the overdense part of the target.

scholarly journals PROJECT OF A BEAMLINE FOR THE NESTOR STORAGE RING LINAC TO PROVIDE NUCLEAR PHYSICS RESEARCH

2021 ◽  
pp. 38-44
Author(s):  
V.V. Mytrochenko ◽  
S.O. Perezhogin ◽  
V.A. Kushnir ◽  
V.B. Ganenko ◽  
M.I. Ayzatsky ◽  
...  
Keyword(s):  
Storage Ring ◽  
Nuclear Physics ◽  
High Energy Physics ◽  
High Energy ◽  
Particle Energy ◽  
Electron Gun ◽  
Dynamics Simulation ◽  
Transport Line ◽  
Beam Dynamics Simulation ◽  
Energy Physics

The results of self-consistent beam dynamics simulation are presented for the linac of the NESTOR storage ring. Consideration is given to the influence of particle energy change at the output of the electron gun during the current pulse. The obtained data have formed the basis for the computation of the beam transport line for research in the field of high energy physics.

scholarly journals ELBE Center for High-Power Radiation Sources

2016 ◽  
Vol 2 ◽  
Author(s):  
Peter Dr. Michel
Keyword(s):  
High Power ◽  
Nuclear Physics ◽  
Thz Radiation ◽  
Linear Electron ◽  
Radiation Sources ◽  
Laser Systems ◽  
Neutron Time ◽  
Γ Rays ◽  
Power Radiation ◽  
High Power Radiation

<p><span style="font-family: Calibri;">In the ELBE Center for High-Power Radiation Sources, the superconducting linear electron accelerator ELBE, serving  two free electron lasers, sources for intense coherent THz radiation, mono-energetic positrons, electrons, γ-rays, a neutron time-of-flight system as well as two synchronized ultra-short pulsed Petawatt laser systems are collocated. The characteristics of these beams make the ELBE center a unique research instrument for a variety of external users in fields ranging from material science over nuclear physics to cancer research, as well as scientists of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR).</span></p>

scholarly journals Scaling of magnetic dissipation and particle acceleration in ABC fields

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Qiang Chen ◽  
Krzysztof Nalewajko ◽  
Bhupendra Mishra
Keyword(s):  
Particle Acceleration ◽  
Magnetic Energy ◽  
Electric Energy ◽  
System Size ◽  
High Energy ◽  
Particle Energy ◽  
Growth Time ◽  
Two Dimensional ◽  
Energy Fraction ◽  
High Energy Part

Using particle-in-cell numerical simulations with electron–positron pair plasma, we study how the efficiencies of magnetic dissipation and particle acceleration scale with the initial coherence length $\lambda _0$ in relation to the system size $L$ of the two-dimensional ‘Arnold–Beltrami–Childress’ (ABC) magnetic field configurations. Topological constraints on the distribution of magnetic helicity in two-dimensional systems, identified earlier in relativistic force-free simulations, that prevent the high- $(L/\lambda _0)$ configurations from reaching the Taylor state, limit the magnetic dissipation efficiency to about $\epsilon _{\textrm {diss}} \simeq 60\,\%$ . We find that the peak growth time scale of the electric energy $\tau _{E,{\textrm {peak}}}$ scales with the characteristic value of initial Alfvén velocity $\beta _{A,{\textrm {ini}}}$ like $\tau _{E,\textrm {peak}} \propto (\lambda _0/L)\beta _{A,{\textrm {ini}}}^{-3}$ . The particle energy change is decomposed into non-thermal and thermal parts, with non-thermal energy gain dominant only for high initial magnetisation. The most robust description of the non-thermal high-energy part of the particle distribution is that the power-law index is a linear function of the initial magnetic energy fraction.

scholarly journals Particle Energization in Relativistic Plasma Turbulence: Solenoidal versus Compressive Driving

2021 ◽  
Vol 922 (2) ◽  
pp. 172
Author(s):  
Vladimir Zhdankin
Keyword(s):  
Particle Acceleration ◽  
Electric Fields ◽  
Large Scale ◽  
High Energy ◽  
Particle Energy ◽  
Density Fluctuations ◽  
Driving Mechanism ◽  
Ion Temperature ◽  
Driving Mechanisms ◽  
Particle Energization

Abstract Many high-energy astrophysical systems contain magnetized collisionless plasmas with relativistic particles, in which turbulence can be driven by an arbitrary mixture of solenoidal and compressive motions. For example, turbulence in hot accretion flows may be driven solenoidally by the magnetorotational instability or compressively by spiral shock waves. It is important to understand the role of the driving mechanism on kinetic turbulence and the associated particle energization. In this work, we compare particle-in-cell simulations of solenoidally driven turbulence with similar simulations of compressively driven turbulence. We focus on plasma that has an initial beta of unity, relativistically hot electrons, and varying ion temperature. Apart from strong large-scale density fluctuations in the compressive case, the turbulence statistics are similar for both drives, and the bulk plasma is described reasonably well by an isothermal equation of state. We find that nonthermal particle acceleration is more efficient when turbulence is driven compressively. In the case of relativistically hot ions, both driving mechanisms ultimately lead to similar power-law particle energy distributions, but over a different duration. In the case of nonrelativistic ions, there is significant nonthermal particle acceleration only for compressive driving. Additionally, we find that the electron-to-ion heating ratio is less than unity for both drives, but takes a smaller value for compressive driving. We demonstrate that this additional ion energization is associated with the collisionless damping of large-scale compressive modes via perpendicular electric fields.

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