Final Report for DoE Grant DE-FG02-06ER54878, Laboratory Studies of Reconnection in Magnetically Confined Plasmas

The study of the collisionless magnetic reconnection constituted the primary work carried out under this grant. The investigations utilized two magnetic configurations with distinct boundary conditions. Both configurations were based upon the Versatile Toroidal Facility (VTF). The first configuration is characterized by open boundary conditions where the magnetic field lines interface directly with the vacuum vessel walls. The reconnection dynamics for this configuration has been methodically characterized and it has been shown that kinetic effects related to trapped electron trajectories are responsible for the high rates of reconnection observed. This type of reconnection has not been investigated before. Nevertheless, the results are directly relevant to observations by the Wind spacecraft of fast reconnection deep in the Earth magnetotail. The second configuration was developed to be specifically relevant to numerical simulations of magnetic reconnection, allowing the magnetic field-lines to be contained inside the device. The configuration is compatible with the presence of large current sheets in the reconnection region and reconnection is observed in fast powerful bursts. These reconnection events facilitate the first experimental investigations of the physics governing the spontaneous onset of fast reconnection. In this Report we review the general motivation of this work, the experimental set-up, and the main physics results

Calculating the chiral condensate diagrammatically at strong coupling

We calculate the chiral condensate of QCD at infinite coupling as a function of the number of fundamental fermion flavours using a lattice diagrammatic approach inspired by recent work of Tomboulis, and other work from the 80's. We outline the approach where the diagrams are formed by combining a truncated number of sub-diagram types in all possible ways. Our results show evidence of convergence and agreement with simulation results at small Nf. However, contrary to recent simulation results, we do not observe a transition at a critical value of Nf. We further present preliminary results for the chiral condensate of QCD with symmetric or adjoint representation fermions at infinite coupling as a function of Nf for Nc = 3. In general, there are sources of error in this approach associated with miscounting of overlapping diagrams, and over-counting of diagrams due to symmetries. These are further elaborated upon in a longer paper.Comment: presented at the 32nd International Symposium on Lattice Field Theory (Lattice 2014), 23-28 June 2014, New York, NY, US

Big Universe, Big Data: Machine Learning and Image Analysis for Astronomy

Astrophysics and cosmology are rich with data. The advent of wide-area digital cameras on large aperture telescopes has led to ever more ambitious surveys of the sky. Data volumes of entire surveys a decade ago can now be acquired in a single night and real-time analysis is often desired. Thus, modern astronomy requires big data know-how, in particular it demands highly efficient machine learning and image analysis algorithms. But scalability is not the only challenge: Astronomy applications touch several current machine learning research questions, such as learning from biased data and dealing with label and measurement noise. We argue that this makes astronomy a great domain for computer science research, as it pushes the boundaries of data analysis. In the following, we will present this exciting application area for data scientists. We will focus on exemplary results, discuss main challenges, and highlight some recent methodological advancements in machine learning and image analysis triggered by astronomical applications

Balanced Wonder: A Philosophical Inquiry into the Role of Wonder in Human Flourishing

The phenomenon of wonder has fascinated scholars for centuries, yet today the subject is understudied and not rooted in any specific academic discipline. Attempts at building a preliminary account of wonder reveals that the experience of wonder is characterised by seven properties: wonder (1) is sudden, extraordinary and personal; (2) intensifies the cognitive focus; (3) intensifies the use of imagination; (4) instigates awareness of ignorance; (5) causes temporary displacement; (6) makes the world newly present; and (7) brings emotional upheaval. Furthermore, wonder can be distinguished from other similar altered states, including awe, horror, the sublime, curiosity, amazement, admiration and astonishment. Human flourishing is a concept in ethics that has enjoyed a revival since Elizabeth Anscombe’s 1958 article ‘Modern Moral Philosophy’. Through the work of Neo-Aristotelian philosophers Douglas Rasmussen, Alasdair McIntyre and Martha Nussbaum who have contributed to the field a working model of human flourishing attentive to human nature was established. As a result of in-depth examination of the contribution of both emotion and imagination in the experience of wonder through a Neo-Aristotelian lens it becomes evident that wonder may contribute to human flourishing via a number of effects, including (but not restricted to) widening of perception, extension of moral scope or sensitivity and prompting deep wonder, a wondrous afterglow, openness, humility, an imaginative attitude, reverence and gratitude. Importantly, for wonder to act as a strong contributor to human flourishing one needs to wonder at the right (or appropriate) thing, in the right amount, in the right time, in the right way and for the right purpose. Cultivating a balanced sense of wonder is thus by no means an easy task but having a critical attitude towards one’s wonderment would aid one to wonder in a virtuous way