No abstract

No abstract

The European XFEL delivers up to 27000 intense (>1012 photons) pulses per second, of ultrashort (≤50 fs) and transversely coherent X-ray radiation, at a maximum repetition rate of 4.5 MHz. Its unique X-ray beam parameters enable groundbreaking experiments in matter at extreme conditions at the High Energy Density (HED) scientific instrument. The performance of the HED instrument during its first two years of operation, its scientific remit, as well as ongoing installations towards full operation are presented. Scientific goals of HED include the investigation of extreme states of matter created by intense laser pulses, diamond anvil cells, or pulsed magnets, and ultrafast X-ray methods that allow their diagnosis using self-amplified spontaneous emission between 5 and 25 keV, coupled with X-ray monochromators and optional seeded beam operation. The HED instrument provides two target chambers, X-ray spectrometers for emission and scattering, X-ray detectors, and a timing tool to correct for residual timing jitter between laser and X-ray pulses.

Science offers many important contributions to achieving the SDGs, of which we highlight two here: first, science generates the basic inputs for innovations, i.e., policy and institutional innovations (including social and business innovations), as well as technology-based innovations to catalyze, support, and accelerate food system transformation; and second, science scrutinizes actions, i.e., assessing ambitions, targets and actions along pathways towards reaching them, for instance, through quantitative analyses and food system modeling. Seven science-driven innovations are elaborated in this chapter, each with some concrete examples. We stress that policy innovations, institutional innovations, and technology innovations are closely connected and actually need to be pursued in an integrated approach. Without accelerated interdisciplinary food system science, the necessary innovations for a sustainable food system will not be achieved. We note the need for systems innovations rather than only single-issue innovations, and call on the science communities to commit to enhanced collaboration among all relevant different disciplines of sciences for this purpose. Moreover, science is not naïve vis á vis power relations: social sciences explicitly uncover them and must identify options for innovations that help to overcome adverse effects. Food system science and food system policy need a stronger framework for constructive and evidence-based interaction for moving ahead. We call upon governments and UN agencies to initiate a process to explore options – existing as well as new – for a strengthened global science-policy interface for a sustainable food system.

For fruitful deliberations and concerted action at the science-politics interface, the concepts of food systems and drivers of change need to be clearly understood and employed by all.

Effects of dust grain charge fluctuation, obliqueness and external magnetic field on a finite-amplitude dust acoustic solitary potential in a magnetized dusty plasma, consisting of electrons, ions and charge-fluctuating dust grains, are investigated using the reductive perturbation method. It is shown that such a magnetized dusty plasma system may support a dust acoustic solitary potential on a very slow time scale involving the motion of dust grains, whose charge is self- consistently determined by local electron and ion currents. The effects of dust grain charge fluctuation, external magnetic field and obliqueness are found to modify the properties of this dust acoustic solitary potential significantly. The implications of these results for some space and astrophysical dusty plasma systems, especially planetary ring systems and cometary tails, are briefly mentioned.

No abstract

The United Nations with its Food Systems Summit 2021 and member countries seek to alter food systems to be healthier, safer, more sustainable, efficient and equitable. This chapter informs about concepts and definitions of food systems and the determinants of their change. To foster a clear understanding of food systems, especially regarding the UN Food Systems Summit and potential follow up to it, we first present a general food systems concept. We then introduce a concept based on science that provides a definition that the UN Food Systems Summit could use with the five goal-oriented Action Tracks (serving SDG2) and their interlinkages. We suggest a food system definition that encompasses food systems thinking and the broad set of actors and drivers, embedding the concept of sustainability within it.