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Supermassive black holes have been known to disrupt passing stars producing outbursts called Tidal Disruption Events offering a unique view on the early stages of accretion disk and jet formation. The advent of large scale optical time-domain surveys has significantly increased the number of known events and challenged our understanding of their dynamics and emission processes. Here, we present the linear polarization curve of the most polarized tidal disruption without any indication of contribution from a jet to the emission. Our observations demonstrate that optical TDE emission can be powered by tidal stream shocks., Comment: 36 pages, 7 figures, author's version of the paper accepted in Science

Funding Information: The work presented in this publication has been carried out by an international research consortium at ABB Drives in Finland, at Aalto University (at Micronova and Nano Microscopy Center) in Finland, at University of Bremen in Germany, and at IWO Ede NL in the Netherlands. We extend special thanks to Jiaco Instruments for the support given by their demonstration of their MIP decapsulation technique which was used for the samples used in this article. We also extend our thanks to Fraunhofer IMWS in Germany for special permission to trial LiT equipment on one of the samples described in this work. The work has been partially funded by the Power2Power project , which is a co-funded European innovation project in the semiconductor industry. The project receives grants from the European H2020 research and innovation programme , the ECSEL Joint Undertaking and national funding authorities from the eight involved countries under grant agreement No 826417 . The participating countries are Austria, Finland, Germany (including the free states of Saxony and Thuringia), Hungary, the Netherlands, Slovakia, Spain and Switzerland. Funding Information: The work presented in this publication has been carried out by an international research consortium at ABB Drives in Finland, at Aalto University (at Micronova and Nano Microscopy Center) in Finland, at University of Bremen in Germany, and at IWO Ede NL in the Netherlands. We extend special thanks to Jiaco Instruments for the support given by their demonstration of their MIP decapsulation technique which was used for the samples used in this article. We also extend our thanks to Fraunhofer IMWS in Germany for special permission to trial LiT equipment on one of the samples described in this work. The work has been partially funded by the Power2Power project, which is a co-funded European innovation project in the semiconductor industry. The project receives grants from the European H2020 research and innovation programme, the ECSEL Joint Undertaking and national funding authorities from the eight involved countries under grant agreement No 826417. The participating countries are Austria, Finland, Germany (including the free states of Saxony and Thuringia), Hungary, the Netherlands, Slovakia, Spain and Switzerland. Publisher Copyright: © 2022 The Author(s) | openaire: EC/H2020/826417/EU//Power2Power In this study, insulated gate bipolar transistor (IGBT) power modules were exposed to high voltage, high humidity, high temperature and reverse bias (HV-H3TRB) conditions until end-of-life (EoL). The limited lifetime of power semiconductor devices when used in demanding applications involving high relative humidity during operation is commonly reported to be associated with the design of the edge termination in power transistor or diode chips. A physics-of-failure (PoF) oriented methodology was adopted in failure analysis, including using lock-in thermography (LiT) for failure localisation and using an advanced microwave-induced plasma (MIP) decapsulation technique for the selective etching of the edge termination polyimide passivation film. A focused ion beam (FIB) was utilised to create a cross-section of the samples for both scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) analysis. The evidence gathered using the physics-of-failure methodology were compared with the results from advanced statistical analysis of the failure distributions in Weibull plots, including comparison of α and β parameters. This analysis revealed correlation with the Weibull distributions and the results from the physics-of-failure. Aluminium corrosion products were systematically observed on guard rings (GR) and field plates (FP) showing that the migration of these corrosion products forming an electrical path between the guard rings that seems to be a major failure mechanism in high humidity environments when reverse bias voltage is applied.

Funding Information: This work has been carried out at ABB Drives and Aalto-University in Finland. The work has been partially funded by the Power2Power project, which is a European co-funded innovation project of the semiconductor industry. The project receives grants from the EU Framework Programme for Research and Innovation H2020 , ECSEL Joint Undertaking , and national funding authorities from eight involved countries under grant agreement No. 826417 . The participating countries are Austria, Finland, Germany (including the Free States of Saxony and Thuringia), Hungary, the Netherlands, Slovakia, Spain and Switzerland. Funding Information: This work has been carried out at ABB Drives and Aalto-University in Finland. The work has been partially funded by the Power2Power project, which is a European co-funded innovation project of the semiconductor industry. The project receives grants from the EU Framework Programme for Research and Innovation H2020, ECSEL Joint Undertaking, and national funding authorities from eight involved countries under grant agreement No. 826417. The participating countries are Austria, Finland, Germany (including the Free States of Saxony and Thuringia), Hungary, the Netherlands, Slovakia, Spain and Switzerland. Publisher Copyright: © 2021 The Authors Power electronics reliability in a high humidity environment has recently been considered an important aspect of power converters. In this article boost stage power semiconductor modules from two vendors with varying device technologies were exposed to high humidity, high temperature and high voltage reverse bias direct current (H3TRB-HVDC) test conditions. The exposed modules were monitored with in situ leakage current measurement during the test. The in situ monitoring revealed that all samples from one vendor using a glass passivation technique failed while the samples from the second vendor with a polyimide passivation survived. After the test, electrical breakdown and associated thermal hotspots were consistently observed using lock-in thermography on top of the glass passivation covering the high voltage edge termination structure. It was concluded with microstructural and material analysis that the treelike structures that were observed right beneath the surface of the glass passivation were associatedwith the failure mechanism. The analysis revealed that the formed structures were amorphous and could not be caused by the electrochemical migration of metallic species. The failures were caused by the localised partial dissolution of lead from the glass passivation. The failure mechanism seems to be associated with water treeing.

Acciari, V. A., et al. (MAGIC Collaboration), PSR J0218+4232 is one of the most energetic millisecond pulsars known and has long been considered as one of the best candidates for very high-energy (VHE; >100 GeV) ?-ray emission. Using 11.5 yr of Fermi Large Area Telescope (LAT) data between 100 MeV and 870 GeV, and ~90 hr of Major Atmospheric Gamma Imaging Cherenkov (MAGIC) observations in the 20 GeV to 20 TeV range, we searched for the highest energy ?-ray emission from PSR J0218+4232. Based on the analysis of the LAT data, we find evidence for pulsed emission above 25 GeV, but see no evidence for emission above 100 GeV (VHE) with MAGIC. We present the results of searches for ?-ray emission, along with theoretical modeling, to interpret the lack of VHE emission. We conclude that, based on the experimental observations and theoretical modeling, it will remain extremely challenging to detect VHE emission from PSR J0218+4232 with the current generation of Imaging Atmospheric Cherenkov Telescopes, and maybe even with future ones, such as the Cherenkov Telescope Array., The financial support of the German BMBF, MPG and HGF; the Italian INFN and INAF; the Swiss National Fund SNF; the ERDF under the Spanish Ministerio de Ciencia e Innovación (MICINN) (FPA2017-87859-P, FPA2017-85668-P, FPA2017-82729-C6-5-R, FPA2017-90566- REDC, PID2019-104114RB-C31, PID2019-104114RB-C32, PID2019-105510GB-C31,PID2019-107847RB-C41, PID2019- 107847RB-C42, PID2019-107988GB-C22); the Indian Department of Atomic Energy; the Japanese ICRR, the University of Tokyo, JSPS, and MEXT; the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-268/16.12.2019 and the Academy of Finland grant No. 320045 is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia “Severo Ochoa” SEV-2016-0588 and CEX2019-000920-S, and “María de Maeztu” CEX2019-000918- M, the Unidad de Excelencia “María de Maeztu” MDM-2015- 0509-18-2 and the “la Caixa” Foundation (fellowship LCF/BQ/ PI18/11630012) and by the CERCA program of the Generalitat de Catalunya; by the Croatian Science Foundation (HrZZ) Project IP2016-06-9782 and the University of Rijeka Project 13.12.1.3.02; by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3; the Polish National Research Centre grant UMO2016/22/M/ST9/00382; and by the Brazilian MCTIC, CNPq and FAPERJ.