Vorsitzende der Sitzung
Diagnostics
- Alexander Sävert (Helmholtz Institut Jena)
Diagnostics
- In diesem Block gibt es keine Vorsitzenden
Diagnostics
- Michael Downer (University of Texas at Austin)
Laser wakefield accelerators (LWFAs) can sustain accelerating gradients that greatly surpass those of conventional accelerators. Long ($\sim$ps) and intense ($>$TW) laser pulses have been employed in LWFAs to generate bright, hard x-rays which are of interest for imaging and diagnosing warm-dense matter. The CO$_2$ laser at the ATF facility of the Brookhaven National Laboratory is a unique...
During laser solid target interactions, the onset of Weibel instability can generate super strong magnetic field structures (up to several $kT$) on the surface and within the bulk of the solid targets. Weibel magnetic fields can be used to understand several physical events in astrophysics [1] as well as impact laser driven inertial confinement fusion process [2] and gamma-ray generation...
The development of next generation laser plasma sources for novel applications in various fields ranging from astro-physics, fusion research to particle acceleration and tumor therapy requires methods to study the plasma dynamics and heating on short spatial (few nanometers) and temporal scales (few femtoseconds). Free electron lasers are identified as a potential new tool to achieve this goal...
The energy density deposited in a highly nonlinear “blowout” regime wake reaches that of the rest energy density of plasma electrons [1]. This energy relaxes through a complex redistribution between e.g. accelerated electrons, undirected hot electrons, ion-channel formation, ionization and excitation of surrounding gas and radiation over ns or longer time scales. These relaxation dynamics...
Laser-wakefield accelerators (LWFA) feature electron bunch durations on a fs-scale. Precise knowledge of the longitudinal profile of such ultra-short electron bunches is essential for the design of future compact X-ray light sources. Resolution limits, as well as the limited reproducibility of electron bunches, pose big challenges for LWFA beam diagnostics.
Spectral measurements of broadband...
Few-cycle microscopy diagnostic [1] combining femtosecond time resolution and micrometer spatial resolution allows for direct observation of laser-driven plasma waves. By comparing the period of the wave train and the independently measured in-situ plasma density, we find that existing 1D models [2, 3] tend to overestimate the contribution of laser intensity to the non-linear plasma wave...
Recent progress in laser wakefield acceleration (LWFA) has demonstrated the generation of high peak current electron beams with improved shot to shot stability [1]. Using high-current electron beams from a LWFA as drivers of a beam-driven plasma wakefield accelerator (PWFA) has been proposed as a beam energy and brightness transformer [2], aiming to fulfill the demanding quality requirements...
To optimize and control GeV-level laser plasma acceleration (LPA), it is important to visualize transient LPA structures in a single shot. In this set of LPA experiments using the Texas Petawatt (~120fs, ~120J) in a plasma of He of density ne < 5 × 1017 cm−3, electrons to (~0.6)GeV were produced in (300pC) bunches. The low repetition-rate and slight fluctuations of the laser motivates...
When it comes online later this fall, FACET-II will begin delivering 10 GeV beams with up to 300 kA peak current and bunch lengths less than 1 µm for a broad range of experiments in advanced accelerator R&D and other novel research directions. Such extreme beam intensities will make diagnostics particularly challenging for FACET-II. Key to the plasma wakefield experimental program is the...
A single-shot hyperspectral camera has been built and a single-shot ultrafast videography protocol has been developed. The camera is capable of retrieving three dimensions of information (two spatial dimensions along with a time or spectral dimension) from a two-dimensional signal of a conventional CCD camera. The third dimension is retrieved using a combination of compressed sensing along...
The development of high-intensity short-pulse lasers in the Petawatt regime offers the possibility to design new compact accelerator schemes by utilizing high-density targets for the generation of high energy ion beams. The optimization of the acceleration process demands comprehensive diagnostic of the plasma dynamics involved, for example via spatially and temporally resolved optical...
In 2018 the first Laser Wakefield Acceleration campaign took place at the Helmholtz-Institute Jena with the JETi-200 laser-system. When travelling through the plasma and exciting a plasma wave, the pump pulse can get scattered at plasma structures depending on the pump pulse’s evolution inside the plasma, the pump pulse‘s chirp and the plasma electron‘s density.
This (stimulated) Raman Side...
We investigate acceleration of ion bunches during relativistically intense laser pulse interactions with plasmas. Relying on coherent acceleration, such laser-driven ion sources feature ion bunch characteristics that can be complementary to those typical of conventional (Wideroe-type) accelerators. Particularly novel intrinsic features include (ultra)short bunch duration, high bunch density,...
New probes are continuously investigated to explore the physics of laser-plasma interactions. Charged particle detection systems and optical probing are well established techniques. The investigation of the bremsstrahlung generated in laser plasma remains, however, a relatively uncommon method to study these interactions.
In this talk we will present the developments in gamma calorimetry...
Few-cycle shadowgraphy is a common tool to qualitatively investigate the longitudinal and transverse structure of laser generated wakefields. However the measured intensity distribution provides hardly any information about the wake amplitude since the wakefield itself is a pure phase object and the measured intensity distribution is a function of the imaging plane. Commonly this plane is not...
The development of second-generation short-pulse laser-driven radiation sources requires a mature understanding of relativistic laser-plasma processes such as plasma oscillations, heating and transport of relativistic electrons as well as the development of plasma instabilities. These dynamic effects occurring on nanometer scales are very difficult to access experimentally during their...
