Physikalisches Institut

Jan 8, 2024 | academic.oup.com | Max-Planck-Institut für Sonnensystemforschung |Technische Universität Braunschweig |Austrian Academy |Physikalisches Institut

Estimation of the properties of the sublimation products leaving the cometary nucleus is one of the significant questions in the study of the dusty-gas flow following the Rosetta mission. It is widely assumed that the temperature of the water molecules emitted is the temperature of ice directly exposed to the surface. However, it is the simplest non-verified idealisation if the refractory porous material lays on the surface and controls the energy driving the ice sublimation.

Nov 9, 2023 | link.aps.org | Fanqi Meng |Physikalisches Institut |J. W. Goethe-Universität |Frederik Walla

We investigate ultrafast harmonic generation (HG) in Si:B, driven by intense pump pulses with fields reaching ∼100kVcm−1 and a carrier frequency of 300 GHz, at 4 K and 300 K, both experimentally and theoretically. We report several findings concerning the nonlinear charge carrier dynamics in intense sub-THz fields: (i) Harmonics of order up to n=9 are observed at room temperature, while at low temperature we can resolve harmonics reaching at least n=11.

Sep 10, 2023 | academic.oup.com | Space Physics |Physikalisches Institut

As a comet approaches the Sun, near-surface ices are heated and sublimate, producing an envelope of expanding neutral gas known as the coma. The coma can be ionized by several processes, generating a population of ions and electrons within it. These form a cometary ionosphere, which interacts with the solar wind. Ionization can be driven by absorption of high energy, extreme ultraviolet (EUV) photons, or by collisions of energetic electrons.

Jun 29, 2023 | link.aps.org | Bernd Wolf |Physikalisches Institut |Jan Zimmermann |Theresa Lundbeck

Abstract We present results of the magnetic susceptibility on high-quality single crystals of EuPd2(Si1−xGex)2 for Ge concentrations 0≤x≤0.105 performed under varying hydrostatic (He-gas) pressure 0≤p≤0.5 GPa. The work extends recent studies at ambient pressure demonstrating the drastic change in the magnetic response from valence-crossover behavior for x=0 and 0.058, to long-range antiferromagnetic (AFM) order below TN=47 K for x=0.105.