Händelser: Centrum: Fysikcentrumhttp://www.chalmers.se/sv/om-chalmers/kalendariumAktuella händelser på Chalmers tekniska högskolaMon, 23 May 2022 10:29:59 +0200http://www.chalmers.se/sv/om-chalmers/kalendariumhttps://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Eleanor-May-220525.aspxhttps://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Eleanor-May-220525.aspxEleanor May, MPPHS fysik<p>PJ, seminar room, Kemigården 1, Fysik Origo</p><p>​Titel på masterarbete: Bayesian History Matching of Chiral Effective Field Theory in the Two-Nucleon Sector Följ presentationen online Lösenord: 902278</p><strong>​Sammanfattning:</strong><div><div>The accurate calculation of nucleon-nucleon scattering observables from first principles is an ongoing challenge within nuclear physics. Working within the framework of chiral effective field theory provides a method for calculating such observables. This is achieved through the construction of an effective Lagrangian that maintains the symmetries of quantum chromodynamics (QCD). In this thesis, truncation of the Lagrangian is performed using a modified Weinberg power counting, introducing a set of unknown low-energy constants at each order in the chiral expansion.</div> <div><br /></div> <div>Bayesian history matching is used to explore the leading order description of the nucleon-nucleon system. This is achieved through the iterative reduction of the four-dimensional parameter space, taking a Bayes linear approach. The history matching implementation is validated on the nuclear liquid drop model. Several novel methods of sampling are introduced within the implementation with the purpose of capturing correlations between parameters; The generation of ellipsoidal distributed samples is shown to be the most successful. History matching is subsequently applied to the proton-neutron scattering problem. We identify the subset of parameter space containing all low-energy constants that produce model outputs consistent with experimental two-nucleon scattering data, accounting for relevant sources of uncertainty. Non-implausible parameter volumes are obtained across a range of momentum regulator cutoffs. Finally, non-implausible samples are used to predict the deuteron binding energy. Results indicate that the inclusion of this observable within the history match could further constrain the volumes.</div> <div><br /></div> <div>The analysis performed in this thesis was successful in producing sets of non-implausible samples. Such sets can be subsequently used as a starting point for a full Bayesian analysis, with the aim of producing posterior probability distributions. For example, the samples can be used to initialise walkers within the Markov Chain Monte Carlo method.</div></div>https://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Anna-Rosén-och-Mohamad-Zoubi--220530.aspxhttps://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Anna-Ros%C3%A9n-och-Mohamad-Zoubi--220530.aspxAnna Rosén och Mohamad Zoubi, MPCAS<p>Physics Soliden, university building, Origovägen 6B, Campus Johanneberg, von Bahr</p><p>​Titel på masterarbete: Generative Modeling for Melanoma Detection Följ presentationen online Lösenord: 133816</p><strong>Sammanfattning:</strong><br /><div>Early detection significantly reduces deaths associated with melanoma, a skin cancer. Despite this information, 80\% of skin cancer related deaths are attributed to malignant melanoma. Melanomas are difficult to diagnose by a dermatologist (skin doctor) therefore many patients undergo unnecessary surgeries to get a biopsy that can confirm the disease. Minimizing unnecessary surgeries would leave more resources that in turn could lead to a higher frequency of earlier diagnosed melanomas. Machine learning algorithms have shown a great potential in the field of medicine and could be deployed to help doctors diagnose melanomas. To obtain a high performing model it is crucial to have a large and balanced dataset. The scarcity of labeled publicly available medical images makes applying machine learning an obstacle in this field, thus hindering development. A solution to this problem could be to synthesize realistic looking images using deep neural networks. One such network is Generative Adversarial Network (GAN), which has been shown successful in producing images in the field of medicine. This thesis explores the generation of synthetic image data for medical purposes and how such data can be evaluated. We utilize StyleGAN2-ADA to generate synthetic images of melanoma lesions that we evaluate using both qualitative and quantitative measures. A survey was made to establish if experts can identify generated images in a mixed dataset. The expert dermatologists found the images difficult to distinguish from real ones, accordingly proving that we can synthesize realistically looking images of melanomas. Using a classifier trained on synthetic melanoma and non-melanoma images we are also able to reach a high accuracy when validating against real data. Our results show that synthetic images are verifiably realistic looking. From our research we are able to conclude that synthetic data can be the answer to further development of classification algorithms in a clinical setting.</div>https://www.chalmers.se/sv/institutioner/mc2/kalendarium/Sidor/shen-zx.aspxhttps://www.chalmers.se/sv/institutioner/mc2/kalendarium/Sidor/shen-zx.aspxGöteborg Mesoscopic Lecture: In Search for the Next Magic Stone<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>Välkommen till Göteborg Mesoscopic Lecture, Summer Lecture 2022 med Zhi-Xun Shen, Depts Physics and Applied Physics, Stanford University, Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory​</p>Kaffe serveras från klockan 15.00<div><strong>​</strong><div><strong>Abstrackt:</strong><div><div>Materials demarcate periods of human civilization. The current period can be argued as defined by silicon, the magic stone that transformed the way we live. In this talk, I will discuss how the concept of quantum, and the 1st wave of quantum revolution led to the rise of silicon, the integrated circuit, Silicon Valley and the information age. I will then discuss the opportunities and challenges beyond silicon, and theoretical ideas and experimental tools needed to enable the next wave of quantum, in search for the next magic stone. </div></div> <div><br /></div> <div><span style="font-weight:700"><img src="/SiteCollectionImages/Institutioner/MC2/Föreläsningar/zhi-xun-shen.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px" />Bio:</span><div><span style="background-color:initial">Dr. Shen is a member of US Ntl Ac Sci, Am Ac Arts &amp; Sci, Chinese Ac Sci. His primary interest is novel quantum phenomena in materials. His work has been recognized  by the E.O. Lawrence Award, the Oliver E. Buckley Prize, the H. Kamerlingh Onnes Prize, and the Einstein Professorship Award of CAS. He has been Chief Scientist of SLAC and director of institutes of material and energy and of the Geballe Laboratory at Stanford University. He has mentored close to one hundred graduate students and post-docs and he is a co-inventor of several patents. </span></div></div> <div><br /></div></div></div>https://www.chalmers.se/sv/institutioner/mc2/kalendarium/Sidor/michael-hein.aspxhttps://www.chalmers.se/sv/institutioner/mc2/kalendarium/Sidor/michael-hein.aspxImpact of equilibration on the heat conductance and noise of non-Abelian fractional quantum Hall edges<p>C511, seminar room, Kemivägen 9, MC2-huset</p><p>Michael Hein, MPNAT Nanotechnology, presenterar sitt examensarbete med titeln &quot;Impact of equilibration on the heat conductance and noise of non-Abelian fractional quantum Hall edges&quot;​</p><div><strong>Handledare</strong>: Christian Spånslätt Rugarn</div> <div><span style="background-color:initial"><b>Examinator</b>: Janine Splettstößer </span></div> <div><span style="background-color:initial"><strong>Opponent</strong>: Victor Lanai</span><span style="background-color:initial"></span><strong><br /></strong></div> <div><strong><br /></strong></div> <div><strong>Abstrakt: </strong></div> <div>In a sufficiently strong magnetic field, a cold 2D electron gas forms fractional quantum Hall states. These are prominently characterized by a quantized Hall conductance and the appearance of 1D edge</div> <div>channels. Certain states, called non-Abelian, are predicted to have exotic particles with potential use for quantum computation. However, unambiguously identifying these states is experimentally challenging since many measurements cannot uniquely distinguish between theoretical candidate states.</div> <div>In this Master thesis defence, I present how to distinguish between non-Abelian candidates for the 5/2 state with edge transport spectroscopy. My focus lies on computing the heat conductance, the generated noise, and their dependence on the degree of thermal equilibration between the edge channels. I compare these results to recent experimental findings.</div>https://www.chalmers.se/sv/institutioner/mc2/kalendarium/Sidor/zhi-xun-shen.aspxhttps://www.chalmers.se/sv/institutioner/mc2/kalendarium/Sidor/zhi-xun-shen.aspxElectronic Phase Diagram of Cuprate Superconductors – a Balancing Act<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>Välkommen till ett seminarium med Zhi-Xun Shen, Depts Physics and Applied Physics, Stanford University, Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory ​</p><strong>​Abstrakt:</strong><div><div>High-temperature superconductivity in copper-based materials, with critical temperature well above what was anticipated by the BCS theory, remains a major unsolved physics problem more than 30 years after its discovery. The problem is fascinating because it is simultaneously simple - being a single band and ½ spin system, yet extremely rich - boasting d-wave superconductivity, pseudogap, spin and charge orders, and strange metal phenomenology. For this reason, cuprates emerge as the most important model system for correlated electrons – stimulating conversations on the physics of the Hubbard model, quantum critical points, Planckian metals and other topics. </div> <div>At the heart of this challenge is the complex electronic phase diagram consisting of intertwined states with unusual properties. Angle-resolved photoemission spectroscopy has emerged as the leading experimental tool to understand the electronic structure of these states and their relationships [1,2]. In this talk, I will describe our results on band structures and Fermi surfaces [3,4]; the d-wave superconducting state [5,6]; the birth of a metal from a Mott insulator [7-11]; the two energy scales of the pseudogap [8,9,12-13]; the temperature, doping and symmetry properties of the low energy pseudogap and its competition with superconductivity [14-18]; the missing quasiparticle and propensity to order [19-21], the interplay of electron-electron and electron-phonon interactions and the enhanced superconductivity [21-24], the incoherent metal sharply bounded by a critical doping [25-26], and the ubiquitous superconducting phase fluctuations [27,28]. The rich phenomenology suggests that a delicate balance between local Coulomb interaction and electron-phonon interaction holds the key to emerging physics in cuprates – unconventional superconductivity, anomalous metal, novel insulator, and intertwined orders.</div></div> <div><br /></div> <div><div>[1] A. Damascelli, Z. Hussain, and Z.-X. Shen, RMP, 75, 473 (2003)     <span style="white-space:pre"> </span><br />[2] J. Sobota, Y.He and Z.-X. Shen, RMP, 93, 025006 (2021)<br /><span style="background-color:initial">[3] D.S. Dessau et al., Phys. Rev. Lett. 66, 2160 (1991)<br /></span><span style="background-color:initial">[4] P. Bogdanov et al., Phys. Rev. Lett. 89, 167002 (2002)<br />[5] Z.-X. Shen et al., Phys. Rev. Lett. 70, 1553 (1993)<br /></span><span style="background-color:initial">[6] M. Hashimoto et al., Nature Physics 10, 483 (2014)<br />[7] B.O. Wells et al., Phys. Rev. Lett. 74, 964 (1995)<br /></span><span style="background-color:initial">[8] D.M. King et al., J. of Phys. &amp; Chem of Solids 56, 1865 (1995)<br />[9] Z.-X. Shen et al., Science 267, 343 (1995)<span style="white-space:pre"><br /></span></span><span style="background-color:initial">[10] N.P. Armitage et al., Phys. Rev. Lett. 87, 147003 (2001) <br />[11] J. He et al. PNAS 116, 9, 3449-3453 (Feb. 2019)<span style="white-space:pre"><br /></span></span><span style="background-color:initial">[12] D.S. Marshall et al., Phy. Rev. Lett. 76, 484 (1996)<br /></span><span style="background-color:initial;white-space:pre"></span></div> <div>[13] A.G. Loeser et al., Science 273, 325 (1996)<span style="white-space:pre"><br /></span>[14] K. Tanaka et al., Science 314, 1910 (2006)<br />[15] W.S. Lee et al., Nature 450, 81 (2007)<span style="white-space:pre"> </span><br />[16] M. Hashimoto et al., Nature Physics 6, 414-418 (2010) <br />[17] R.H. He et al., Science 331, 1579 (2011)<span style="white-space:pre"><br /></span>[18] M. Hashimoto et al., Nature Materials 14, 1 (2015)<br />[19] D.L. Feng et al., Science 289, 277 (2000)<span style="white-space:pre"><br /></span>[20] K.M. Shen et al., Phys. Rev. Lett., 93, 267002 (2004)<br />[21] KM Shen et al., Science 307, 901 (2005)<span style="white-space:pre"><br /></span>[22] A. Lanzara et al., Nature 412, 510 (2001)<br />[23] T. Cuk et al., Phys. Rev. Lett., 93, 117003 (2004)<span style="white-space:pre"><br /></span>[24] Yu He et al., Science, 362, 62 (Oct. 2018)      </div> <div>[25] I.M. Vishik et al., PNAS 109/45, 18332-18337 (2012)<br />[26] S.D. Chen et al., Science 366, 1099 (2019)</div> <div>[27] Y. He et al., Phys. Rev. X, 031068 (2021)<br />[28] S.D. Chen et al., Nature 601, 562 (2022)</div> <div><br /></div></div> <div><br /></div>https://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Adrián-Dewambrechies-Fernández-220603.aspxhttps://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Adri%C3%A1n-Dewambrechies-Fern%C3%A1ndez-220603.aspxAdrián Dewambrechies Fernández, MPPHS fysik<p>PJ, seminar room, Kemigården 1, Fysik Origo</p><p>​Titel på masterarbete: Spectroscopic Characterization of Edges in Transition Metal Dichalcogenide Metastructures Följ presentationen online Lösenord: 581711 ​</p><span style="background-color:initial"><strong>Sammanfattning</strong><span><strong>:  </strong></span></span><span></span><div>Two-dimensional materials have proven to show a very broad spectrum of physical phenomena for the past decades, offering a very important scientific playground, both under an experimental and theoretical point of view. While the family of Transition Metal Dichalcogenides (TMDCs) has overcome most of the problems that prevented graphene to consolidate as a reliable material for a scalable integrated circuit implementation, they still face their own challenges regarding device-to-device variability, and requirements for industry-scalable dimensions. </div> <div>The next step in the understanding of two-dimensional materials is the study of the physics taking place at the edges, which can be very different from its bulk counterpart, these differences ultimately coming from the symmetry breaking in the crystal structure and its consequences on the electronic properties. In this context, this thesis is focused on the characterization of these one-dimensional defects that can be produced in a new kind of metastructures taking place on different TMDC multilayers, with very high-quality in their crystal symmetry and optoelectronic properties. The project will start with production of these physical systems, followed by their characterization via optical and mechanical means, in particular Raman spectroscopy, Second Harmonic Generation (SHG), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM).  </div> <div>This complete vision coming from different corners of the characterization will enlighten the growth process of these metastructures, testing their reliability as a system where the understanding of edge physics can be promoted and developed. </div>https://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Yanuar-Rizki-Pahlevi-220609.aspxhttps://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Yanuar-Rizki-Pahlevi-220609.aspxYanuar Rizki Pahlevi, MPCAS<p>Nexus 4030, meeting room, Kemigården 1, Fysik Origo</p><p>​Titel på masterarbete: Deep Learning for Optical Tweezers: DeepCalib Implementation for Brownian Motion with Delayed Feedback</p><strong>Sammanfattning:</strong><div><div>Brownian motion with delayed feedback theoretically studied to take control of Brownian particle movement’s direction. One can use optical tweezers to implement delayed feedback. Calibrating optical tweezers with delay implemented is not an easy job. In this study, Deep learning technique using Long Short Term Memory(LSTM) layer as main composition of the model to calibrate the trap stiffness andto measure the delayed feedback employed, using the trapped particle trajectory asan input. We demonstrate that this approach is outperforming variance methods inorder to calibrate stiffness, also outperforming approximation method to measure the delay in harmonic trap case.</div></div> <div><br /></div>https://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Ambjorn-Joki-220610.aspxhttps://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Ambjorn-Joki-220610.aspxAmbjörn Joki, MPPHS Physics<p>Physics Soliden, university building, Origovägen 6B, Campus Johanneberg, von Bahr</p><p>​Titel på masterarbete: Electron Phonon Coupling in Perovskites  Följ presentationen online Lösenord: dispersion</p><br /><div></div>https://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Madeleine-Karlsson-220610.aspxhttps://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Madeleine-Karlsson-220610.aspxMadeleine Karlsson, MPPHS fysik<p>Physics Soliden, university building, Origovägen 6B, Campus Johanneberg, vån 3, von Bahr</p><p>​Titel på masterarbete: Towards more efficient solar cells: the effect of dynamical disorder on the electronic structure of halide double perovskites</p><div><div><strong>Sammanfattning:</strong></div> <div>Recently, simple perovskites have attracted great attention as the energy-absorbing material in solar cells. In computational and experimental studies they have shown several desirable properties but also challenges, such as instabilities and toxicity due to the presence of lead. As a solution to the problems connected to the simple perovskites, the double perovskites were suggested as a suitable material in the solar cells of tomorrow. In order to use double perovskites in an application it needs to be thoroughly understood. Within this thesis the octahedral tilting and the band gap of double perovskites have been studied, which is a step towards finding a material that is stable and exhibit the optimal band gap to absorb solar energy. It turns out that the octahedral tilting is not as prominent in all double perovskites as in the simple ones. The statement that the octahedral tilting is due to the presence of lone-pair electrons is considered and it agrees with observations - lone-pair electrons induce octahedral tilting. The effect of octahedral tilting on the band gap of the double perovskites is studied as well and it is concluded that the band gap increases with the tilting. As the global warming increases rapidly it is important to find green solutions and as solar cells are renewable and emission-free they are good candidates for further developement.</div></div>https://www.chalmers.se/sv/institutioner/mc2/kalendarium/Sidor/athanasios-theodoridis-.aspxhttps://www.chalmers.se/sv/institutioner/mc2/kalendarium/Sidor/athanasios-theodoridis-.aspxCharacterization of Graphene based porous structures for noise damping in transmission systems<p>Fasrummet, meeting room, Kemivägen 9, MC2-huset</p><p>​Athanasios Theodoridis, MPNAT Nanotechnology, presenterar sitt examensarbete med titeln &quot;Characterization of Graphene based porous structures for noise damping in transmission systems&quot;​</p>​<strong style="background-color:initial">Handledare: </strong><span style="background-color:initial">Dr. Yifeng Fu (Chalmers), Dr. Flavio Presezniak (Volvo AB)</span><div><strong>Opponent: </strong><span style="background-color:initial">Awse S. A. Salha</span></div> <div><span style="background-color:initial"><strong>Examinator: </strong></span><span style="background-color:initial"></span><span style="background-color:initial">Prof. Johan Liu</span></div> <div><span style="background-color:initial"><br /></span></div> <div><span style="background-color:initial"><strong></strong></span><span style="background-color:initial"><strong>Abstrakt</strong>: Noise pollution is an environmental issue that has been gaining more and more attention over the last years. Heavy machinery such as trucks are a big contributor to this problem, and stricter environmental regulations drive companies into finding better solutions where they can keep noise levels to a minimum, while still being profitable. Recently developed porous graphene films (PGFs) can be a promising solution, since they are thin, lightweight and industrially produced. Due to their film structure and inherent porosity, in the form of air pockets, they are studied, for the first time, for their potential to be incorporated into today's acoustic applications. In this project, PGFs are investigated in terms of their thermal, structural and acoustical properties. For the first two, several characterization methods are employed, namely a self-heating method, the buoyancy method, tensile stress measurements, BET analysis and SEM imaging, among others. For the latter impedance tube measurements are conducted, in order to investigate the acoustic performance and characterize the PGFs in terms of their acoustic properties. For that matter, both measurements on sample acoustic devices and simulations are employed. Thin membrane-type acoustic devices are designed and fabricated where they exhibit absorption peaks in the low-frequency range and are compared with today's standard acoustic materials that are used in the automotive industry. Additionally, acoustical characterization leads to the estimation of certain material parameters, which are then used in the JCA model to simulate different device configurations. Simulations have shown, that in applications consisting of PU/fabric structures, the substitution of the thin fabric with a graphene film, can improve the sound absorption performance and also shift the absorption peak to lower frequencies. Finally, the recyclability of waste PGFs is investigated, in which graphene film pieces are crushed and shear exfoliated into graphene powder. This graphene powder can later be incorporated into various applications.</span></div> <div><span style="background-color:initial"><br /></span></div> <div><span style="background-color:initial"><br /></span></div>https://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Hannes-Bergstrom-och-Peter-Halldestam-220610.aspxhttps://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Hannes-Bergstrom-och-Peter-Halldestam-220610.aspxHannes Bergström och Peter Halldestam, MPPHS fysik<p>PJ, seminar room, Kemigården 1, Fysik Origo</p><p>​Titel på masterarbete: Optimization of tokamak disruption scenarios: avoidance of runaway electrons and excessive wall loads Följ presentationen online Lösenord: optimize</p><strong>​Sammanfattning:</strong><div><div>Research in the field of fusion science has been propelled by its potential to alleviate humanity's reliance on fossil fuels. </div> <div>One of today's most promising approaches to generating thermonuclear fusion energy uses magnetic confinement of hydrogen fuel in the plasma state. The tokamak concept, which has achieved the best fusion performance so far, is used in the two devices (ITER and SPARC) currently being constructed -- they aim to achieve a positive energy balance, thereby demonstrating the scientific feasibility of magnetic confinement fusion energy. </div> <div><br /></div> <div>A major open issue threatening the success of these tokamaks is plasma disruption. In these off-normal events the plasma loses most of its thermal energy on a millisecond timescale, exposing the device to excessive mechanical stress and heat loads. In addition, in the high-current devices currently under construction, one of the most important related problems is posed by currents carried by electrons accelerated to relativistic energies, called runaway electrons. If these were to strike the inner wall unmitigated, it may cause potentially irreversible damage to the device. The methods proposed to mitigate these dangerous effects of disruptions, such as massive material injection, are characterized by a large number of parameters, such as when to inject material, in which form and composition. This poses an optimization problem which involves a potentially high dimensional parameter space and a large number of disruption simulations. </div> <div><br /></div> <div>In this work, we have developed an optimization framework which we apply to numerical disruption simulations of plasmas representative of ITER, aiming to find initial conditions for which large runaway beams and excessive wall loads can be avoided. We assess the performance of mitigation when inducing the disruption by massive material injection of neon and deuterium gas. The optimization metric takes into account the maximum runaway current, the transported fraction of the heat loss -- affecting heat loads -- and the temporal evolution of the ohmic plasma current -- determining the forces acting on the device. </div></div>https://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Esmée-Berger-220610.aspxhttps://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Esm%C3%A9e-Berger-220610.aspxEsmée Berger, MPPHS fysik<p>PJ, seminar room, Kemigården 1, Fysik Origo</p><p>​Titel på masterarbete: Runaway dynamics in reactor scale spherical tokamak disruptions Följ presentationen online Lösenord: step</p><strong>Sammanfattning:</strong><br /><span style="background-color:initial"></span><div>One of the most promising concepts to achieve commercial fusion power, to date, is a toroidal magnetic confinement system centered around a tokamak. To aid the development, compact spherical tokamaks have long been proposed as component testing facilities. There is also an effort to design and construct spherical tokamaks suitable for energy production, with an example being the STEP program in the UK. One of the remaining obstacles for all reactor-scale tokamaks is so-called runaway electrons -- electrons accelerated to relativistic speeds. These can be generated during disruptions, which are off-normal events where the confinement of the plasma is rapidly lost. As runaway electrons can severely damage the machine walls, their production and mitigation has been extensively studied for conventional tokamaks. However, due to the disruption dynamics typically being different in spherical tokamaks, the existing results cannot directly be transferred to these more compact devices. Therefore, runaway dynamics in reactor-scale spherical tokamaks is investigated in this work, and we study both the severity of runaway generation during unmitigated disruptions, as well as the effect that typical mitigation schemes based on massive material injection have on runaway production. The study is conducted using the numerical framework DREAM (Disruption and Runaway Electron Avoidance Model) and we find that, in many cases, mitigation strategies are necessary if the runaway current is to be prevented from reaching multi-megaampere levels. Our results indicate that with a suitably chosen deuterium-neon mixture for mitigation, it is possible to achieve a tolerable runaway current and ohmic current evolution. With such parameters, however, the majority of the thermal energy loss happens through radial transport rather than radiation, which poses a risk of unacceptable localized heat loads.</div>https://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Licentiatseminarium-Konstantinos-Papadopoulos-220613.aspxhttps://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Licentiatseminarium-Konstantinos-Papadopoulos-220613.aspxKonstantinos Papadopoulos, Fysik<p>PJ, seminar room, Kemigården 1, Fysik Origo</p><p>​Titel på licentiatuppsats: Correlation effects in ionic perovskite crystals</p><strong>​​​</strong><div><strong>Sammanfattning</strong>: </div>https://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Linnea-Rensmo-220614.aspxhttps://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Linnea-Rensmo-220614.aspxLinnea Rensmo, MPPHS Fysik<p>PJ, seminar room, Kemigården 1, Fysik Origo</p><p>​Titel på masterarbete: Characterization of HDPE using small and wide angle scattering</p><strong>Sammanfattning:</strong><div></div> <div><div>The importance of polymers in materials science can not be underestimated. Polymers are widely used within everything from clothing and  electronics to packages and paint. Tetra Pak uses the polymer high-density polyethylene, or HDPE, for their packaging solutions. The plastic material HDPE has the advantageous properties of being moldable and sturdy. To build understanding of what structures gives rise to these properties it is important to characterize the material. If the structure is known, it is perhaps possible to manufacture a similar material, in the future, that is not made from oil. This work focuses on the characterization of the material. The structures of HDPE are investigated with small and wide angle scattering.</div> <div style="font-weight:bold"><br /></div></div>https://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Installationsfrelasning-Sverker-Holmgren.aspxhttps://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Installationsfrelasning-Sverker-Holmgren.aspxInstallationsföreläsning, Sverker Holmgren<p>Nexus 4030, meeting room, Kemigården 1, Fysik Origo</p><p>​Välkommen att delta vid Sverker Holmgrens installationsföreläsning som forskningsprofessor vid institutionen för fysik.</p>​<img src="/SiteCollectionImages/Areas%20of%20Advance/Information%20and%20Communication%20Technology/News%20events/eCommons/SverkerHolmgren_FotoTerjeHeiestad.jpg" alt="Sverker Holmgren" class="chalmersPosition-FloatRight" style="margin:5px;width:145px;height:194px" />Titel på föreläsningen meddelas inom kort.​<span style="background-color:initial"></span>https://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Linus-Sundberg-220614.aspxhttps://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Masterpresentation-Linus-Sundberg-220614.aspxLinus Sundberg, MPPHS Physics<p>PJ, seminar room, Kemigården 1, Fysik Origo</p><p>Tit​el på masterarbete: Extended geometry and magical supergravities</p><strong>Sammanfattning:</strong><br /><span style="background-color:initial"></span><div><span style="background-color:initial">During the last decades double and exceptional field theory have been introduced in an attempt to understand the dualities of compactified supergravities from a geometrical perspective. There has been much work done on this subject where the exceptional field theories have been intended to understand the symmetries of M-theory. However, there exists another class of supergravities, which has deep ties to the Lie groups found in the magical square of Lie algebras, and which has yet to be understood to full extent. The aim of this thesis is to understand and develop a formalism using extended geometry for the non-gauged magical supergravities, more specifically the bosonic sector, in various external dimensions. This includes a systematic investigation of solutions of the section constraint for general real form of the internal structure algebra. </span></div>https://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Licentiatseminarium-Linnea-Bjorn-220617.aspxhttps://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Licentiatseminarium-Linnea-Bjorn-220617.aspxLinnea Björn, Materialvetenskap<p>PJ, seminar room, Kemigården 1, Fysik Origo</p><p>​​Titel på licentiatuppsats: Characterization of injection molded polymers: from conventional to wood-based thermoplastics</p>​<div><strong>Sammanfattning</strong>: </div>https://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Licentiatseminarium-Leonard-Nielsen-220617.aspxhttps://www.chalmers.se/sv/institutioner/fysik/kalendarium/Sidor/Licentiatseminarium-Leonard-Nielsen-220617.aspxLeonard Nielsen, Fysik<p>PJ, seminar room, Kemigården 1, Fysik Origo</p><p>​Titel på licentiatuppsats: Theoretical and computational advances in small-angle x-ray scattering tensor tomography</p>​<div><strong>Sammanfattning</strong>: </div>