Institutskolloquium des IPP 2017

Data from the German electricity system for the years 2010, 2012, 2013, and 2015 are used and scaled up to a 100% supply by intermittent renewable energy sources (iRES). In the average, 330 GW wind and PV power are required to meet a 100% target. A back-up system is necessary with the power of 89% of peak load. Surplus electricity accrues at high power levels. Curtailing surplus power to a large extent is found to be uneconomic. Demand-side-management will suffer from the strong day-to-day variation of available surplus energy. A day storage is ineffective because of the day-night correlation of surplus power during winter. A seasonal storage loses its character when transformation losses are considered because it can contribute only after periods with excessive surplus production. The capacities to be installed stress the difficulty to base heat supply and mobility also on iRES generated electricity in the future. As the German energy transition replaces one CO₂-free electricity supply system by another one no major reduction in CO₂ emission can be expected till the last nuclear reactor will be switched off. The German GHG emission targets for 2020 and beyond may be in jeopardy. [mehr]

Plasma wakes, excited by short high-power laser pulses or short bunches of relativistic charged particles passing through the plasma, give rise to strong longitudinal electric fields which can be employed to accelerate electrons. The accelerating gradients achieved in a plasma wakefield can exceed those of accelerating structures typically used in state-of-the-art particle accelerators by three to four orders of magnitude. Since the scale of accelerator-driven research facilities drives their construction and operation cost on the one hand and limits their range of applications on the other, it appears extremely attractive to utilize plasma-wakefield accelerating techniques in future: one may dream of X-ray free electron lasers fitting into university laboratories and hospitals or of TeV electron-positron colliders less than one kilometer long instead of requiring a 50 to 100 kilometer long tunnel passing beneath the Lake Geneva. Therefore, since the first experimental demonstration of the acceleration of plasma background electrons in the so-called wave-breaking regime of laser wakefield acceleration in 2004 a steadily increasing R&D effort in laser, plasma and accelerator physics has been devoted to this topic.In my talk I will give a - non-exhaustive - review of the current status of laser wakefield electron accelerators and introduce the particular challenges one is facing if one intends to combine laser wakefield and "conventional" accelerator techniques in order to realize synchrotron light sources or even free electron lasers. I will present our ideas on how to possibly cope with some of these challenges. [mehr]