Propagation-enhanced generation of intense high-harmonic continua in the 100-eV spectral region

The study of core electron dynamics through nonlinear spectroscopy requires intense isolated attosecond extreme ultraviolet or even X-ray pulses. A robust way to produce these pulses is high-harmonic generation (HHG) in a gas medium. However, the energy upscaling of the process depends on a very demanding next-generation laser technology that provides multi-terawatt (TW) laser pulses with few-optical-cycle duration and controlled electric field. Here, we revisit the HHG process driven by 16-TW sub-two-cycle laser pulses to reach high intensity in the 100-eV spectral region and beyond. We show that the combination of above barrier-suppression intensity with a long generation medium significantly enhances the isolation of attosecond pulses compared to lower intensities and/or shorter media and this way reduces the pulse duration as well as field-stability requirements on the laser driver. This novel regime facilitates the real-time observation of electron dynamics at the attosecond timescale in atoms, molecules, and solids

Microthrombotic renal involvement in an SLE patient with concomitant catastrophic antiphospholipid syndrome: the beneficial effect of rituximab treatment

LBK

Tabletop nonlinear optics in the 100-eV spectral region

Nonlinear light-matter interactions in the extreme ultraviolet (XUV) are a prerequisite to perform XUV-pump/XUV-probe spectroscopy of core electrons. Such interactions are now routinely investigated at free-electron laser (FEL) facilities. Yet, electron dynamics are often too fast to be captured with the femtosecond resolution of state-of-the-art FELs. Attosecond pulses from laser-driven XUV-sources offer the necessary temporal resolution. However, intense attosecond pulses supporting nonlinear processes have only been available for photon energy below 50 eV, precluding XUV-pump/XUV-probe investigation of typical inner-shell processes. Here, we surpass this limitation by demonstrating two-photon absorption from inner electronic shells of xenon at photon energies around 93 eV and 115 eV. This advance opens the door for attosecond real-time observation of nonlinear electron dynamics deep inside atoms

Quasimonoenergetic electron acceleration in the self-modulated laser wakefield regime

Details on the generation of (multiple) quasimonoenergetic electron bunches in the self-modulated laser wakefield acceleration (SMLWFA) regime are presented. This type of laser-plasma interaction can result in pronounced longitudinal laser pulse fragmentation, dependent on plasma density and laser intensity. It is shown by experiments and particle-in-cell simulations that these laser pulse fragments can be powerful enough to trigger nonlinear plasma wave breaking, injection, and acceleration of electrons to quasimonoenergetic energies. With high plasma densities, self-modulation is promoted, and the advantages of SMLWFA such as especially high accelerating fields and short electron bunches (<5 fs) can be harvested. In addition, more than one quasimonoenergetic electron bunch can be created, with a temporal spacing between each bunch of only few tens of femtoseconds, again governed by plasma density

Quasi-monoenergetic electron acceleration : the self-modulated multi-bubble regime

[Abstract unavailable

Novel method for characterizing relativistic electron beams in a harsh laser-plasma environment

Particle pulses generated by laser-plasma interaction are characterized by ultrashort duration, high particle density, and sometimes a very strong accompanying electromagnetic pulse (EMP). Therefore, beam diagnostics different from those known from classical particle accelerators such as synchrotrons or linacs are required. Easy to use single-shot techniques are favored, which must be insensitive towards the EMP and associated stray light of all frequencies, taking into account the comparably low repetition rates and which, at the same time, allow for usage in very space-limited environments. Various measurement techniques are discussed here, and a space-saving method to determine several important properties of laser-generated electron bunches simultaneously is presented. The method is based on experimental results of electron-sensitive imaging plate stacks and combines these with Monte Carlo-type ray-tracing calculations, yielding a comprehensive picture of the properties of particle beams. The total charge, the energy spectrum, and the divergence can be derived simultaneously for a single bunch

Absolute charge calibration of scintillating screens for relativistic electron detection

We report on new charge calibrations and linearity tests with high-dynamic range for eight different scintillating screens typically used for the detection of relativistic electrons from laser-plasma based acceleration schemes. The absolute charge calibration was done with picosecond electron bunches at the ELBE linear accelerator in Dresden. The lower detection limit in our setup for the most sensitive scintillating screen (KODAK Biomax MS) was 10 fC/ mm 2. The screens showed a linear photon-to-charge dependency over several orders of magnitude. An onset of saturation effects starting around 10-100 pC/ mm2 was found for some of the screens. Additionally, a constant light source was employed as a luminosity reference to simplify the transfer of a one-time absolute calibration to different experimental setups

Effect of genotypic, meteorological and agronomic factors on the gluten index of winter durum wheat

The determination of the gluten index is a widely used method for analysing the gluten strength of bread wheat and spring durum wheat genotypes. The present work was carried out to study the effect of the genotype, meteorological factors (temperature, precipitation and number of days with Tmax ≥ 30 °C) and agronomic treatments (N fertilisation and plant protection) on the gluten index of winter durum wheat varieties and breeding lines. The results indicated that the gluten index had little dependence on the environment, being determined to the greatest extent by the genotype. Compared with varieties having weak gluten, those with a strong gluten matrix responded less sensitively to changes in environmental conditions. Among the meteorological factors, high temperature at the end of the grain-filling period caused the greatest reduction in the mean gluten index of three varieties (R 2 = 0.462), while the fertiliser was found to be a significant factor affecting the gluten strength of winter durum wheat varieties. Using selection based on the gluten index, the gluten strength of winter durum wheat lines can be improved sufficiently to make them competitive with high quality spring varieties

Genetic architecture of common bunt resistance in winter wheat using genome-wide association study

Background: Common bunt (caused by Tilletia caries and T. foetida) has been considered as a major disease in wheat (Triticum aestivum) following rust (Puccinia spp.) in the Near East and is economically important in the Great Plains, USA. Despite the fact that it can be easily controlled using seed treatment with fungicides, fungicides often cannot or may not be used in organic and low-input fields. Planting common bunt resistant genotypes is an alternative. Results: To identify resistance genes for Nebraska common bunt race, the global set of differential lines were inoculated. Nine differential lines carrying nine different genes had 0% infected heads and seemed to be resistant to Nebraska race. To understand the genetic basis of the resistance in Nebraska winter wheat, a set of 330 genotypes were inoculated and evaluated under field conditions in two locations. Out of the 330 genotypes, 62 genotypes had different degrees of resistance. Moreover, plant height, chlorophyll content and days to heading were scored in both locations. Using genome-wide association study, 123 SNPs located on fourteen chromosomes were identified to be associated with the resistance. Different degrees of linkage disequilibrium was found among the significant SNPs and they explained 1.00 to 9.00% of the phenotypic variance, indicating the presence of many minor QTLs controlling the resistance. Conclusion: Based on the chromosomal location of some of the known genes, some SNPs may be associated with Bt1, Bt6, Bt11 and Bt12 resistance loci. The remaining significant SNPs may be novel alleles that were not reported previously. Common bunt resistance seems to be an independent trait as no correlation was found between a number of infected heads and chlorophyll content, days to heading or plant height