High-brightness betatron emission from the interaction of a sub picosecond laser pulse with pre-ionized low-density polymer foam for ICF research.

Direct laser acceleration (DLA) of electrons in plasmas of near-critical density (NCD) is a very advancing platform for high-energy PW-class lasers of moderate relativistic intensity supporting Inertial Confinement Fusion research. Experiments conducted at the PHELIX sub-PW Nd:glass laser demonstrated application-promising characteristics of DLA-based radiation and particle sources, such as ultra-high number, high directionality and high conversion efficiency. In this context, the bright synchrotron-like (betatron) radiation of DLA electrons, which arises from the interaction of a sub-ps PHELIX laser pulse with an intensity of 1019 W/cm2 with pre-ionized low-density polymer foam, was studied. The experimental results show that the betatron radiation produced by DLA electrons in NCD plasma is well directed with a half-angle of 100-200 mrad, yielding (3.4 ± 0.4)·1010 photons/keV/sr at 10 keV photon energy. The experimental photon fluence and the brilliance agree well with the particle-in-cell simulations. These results pave the way for innovative applications of the DLA regime using low-density pre-ionized foams in high energy density research.

Generation of multi-millijoule red-shifted pulses for seeding stimulated Raman backscattering amplifiers.

The efficient generation of redshifted pulses from chirped femtosecond joule level Bessel beam pulses in gases is studied. The redshift spans from a few 100 cm⁻¹ to several 1000 cm⁻¹ corresponding to a shift of 50-500 nm for Nd:glass laser systems. The generated pulses have an almost perfect Gaussian beam profile insensitive of the pump beam profile, and are much shorter than the pump pulses. The highest measured energy is as high as 30 mJ, which is significantly higher than possible with solid state nonlinear frequency shifters.

[Pouring water over the body--hydrotherapy prescriptions in the late Middle Ages]. / Die Ubergiessung mit Wasser--Hydrotherapeutische Vorschriften im Spätmittelalter.

Once identified, an illness is met or fought against by an appropriate therapy. The diverse use of water holds a significant place among the therapeutic means which had been developed in Western medicine ever since antiquity. The essay deals with one particular form of application, namely, the gush of water. Focus is laid on the period around 1500. As the relevant medical treatises are based directly on Greek or Roman authors (Hippocrate, Galen, Celsus) or are even commentaries of Arabic handbooks in their Latin translations (Avicenna, Rhazes), antique medicine inevitably had also to be taken into account. The pouring of water, alone or in combination with other prescriptions, was applicable in a variety of illnesses as fevers, pains of the joints, psychic diseases, or even headaches. To counteract the causes (or symptoms) of a disease the water quality could be adjusted by changing its temperature, by adding certain substances (oils, herb extracts or decoctions) or by varying the way of application. The gush of water could serve many purposes and was prescribed to soothe, to refrigerate, to stop a swelling, to widen pores, to shock the patient and even, given the underlying humoural conception of men's nature, to draw away humours from one part of the body to another. The water gush, hence, was not restricted to be used in the case of one particular illness only but was considered an almost general therapeutic means.