Neutrinos in dense quark matter and cooling of compact stars

We discuss that observational constraints on neutrino cooling processes may restrict the spectrum of quark matter phases admissible for compact star interiors.Comment: 3 pages, contribution to International School of Nuclear Physics on "Neutrinos in Cosmology, in Astro-, Particle- and Nuclear Physics, Erice-Sicily, September 16-24, 200

Neutrino emissivities and bulk viscosity in neutral two-flavor quark matter

We study thermodynamic and transport properties for the isotropic color-spin-locking (iso-CSL) phase of two-flavor superconducting quark matter under compact star constraints within a NJL-type chiral quark model. Chiral symmetry breaking and the phase transition to superconducting quark matter leads to a density dependent change of quark masses, chemical potentials and diquark gap. A self-consistent treatment of these physical quantities influences on the microscopic calculations of transport properties. We present results for the iso-CSL direct URCA emissivities and bulk viscosities, which fulfill the constraints on quark matter derived from cooling and rotational evolution of compact stars. We compare our results with the phenomenologically successful, but yet heuristic 2SC+X phase. We show that the microscopically founded iso-CSL phase can replace the purely phenomenological 2SC+X phase in modern simulations of the cooling evolution for compact stars with color superconducting quark matter interior.Comment: 15 pages, 6 figures, references added, text improve

Ionospheric response during low and high solar activity

We analyse solar extreme ultraviolet (EUV) irradiance observed by the Solar EUV Experiment (SEE) onboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite, and solar proxies (the F10.7 index, and Mg-II index), and compare their variability with the one of the global mean Total Electron Content (GTEC). Cross-wavelet analysis confirms the joint 27 days periodicity in GTEC and solar proxies. We focus on a comparison for solar minimum (2007-2009) and maximum (2013-2015) and find significant differences in the correlation during low and high solar activity years. GTEC is delayed by approximately 1-2 days in comparison to solar proxies during both low and high solar activity at the 27 days solar rotation period. To investigate the dynamics of the delay process, Coupled Thermosphere Ionosphere Plasmasphere electrodynamics model simulations have been performed for low and high solar activity conditions. Preliminary results using cross correlation analysis show an ionospheric delay of 1 day in GTEC with respect to the F10.7 index during low and high solar activity.Wir analysieren vom Solar Extreme Ultraviolet Experiment (SEE) an Bord des Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) Satelliten gemessene solare EUV-Irradianzen, solare Proxies (den F10.7-Index und denMg-II-Index), und vergleichen deren Variabilität mit derjenigen des global gemittelten Gesamtelektronengehalts (GTEC). Kreuzwaveletanalysen bestätigen eine gemeinsame Variabilität im Periodenbereich der solaren Rotation (27 Tage). Wir vergleichen insbesondere den Zusammenhang während des solaren Minimums (2007- 2009) und Maximums (2013-2015), wobei signifikante Unterschiede der Korrelation zwischen solaren und ionosphärischen Parametern auftreten. Es tritt eine Verzögerung der Maxima und Minima von GTEC gegenüber denjenigen der solaren Proxies von einem Tag sowohl im solaren Minimum als auch im solaren Maximum auf

Evaluating the performance of ionic liquid coatings for mitigation of spacecraft surface charges

To reduce the impact of charging effects on satellites, cheap and lightweight conductive coatings are desirable. We mimic space-like charging environments in ultra-high vacuum (UHV) chambers during deposition of charges via the electron beam of a scanning electron microscope (SEM). We use the charge induced signatures in SEM images of a thin ionic liquid (IL) film on insulating surfaces such as glass, to assess the general performance of such coatings. In order to get a reference structure in SEM, the samples were structured by nanosphere lithography and coated with IL. The IL film (we choose BMP DCA, due to its beneficial physical properties) was applied ex situ and a thickness of 10 to 30 nm was determined by reflectometry. Such an IL film is stable under vacuum conditions. It would also only lead to additional mass of below 20 mg/m$^2$. At about 5 A/m$^2 \approx 3\cdot10^{19}$ e/(s$\cdot$m$^2$), a typical sample charging rate in SEM, imaging is possible with no noticeable contrast changes over many hours; this electron current density is already 6 orders of magnitudes higher than "worst case geosynchronous environments" of $3\cdot10^{-6}$ A/m$^2$. Measurements of the surface potential are used for further insights in the reaction of IL films to the electron beam of a SEM. Participating mechanisms such as polarization or reorientation will are discussed.Comment: Submitted to Proceedings of the 14th IAA Symposium on Small Satellites for Earth System Observatio