12 research outputs found
Plasma Heating Simulation in the VASIMR System
The paper describes the recent development in the simulation of the ion-cyclotron acceleration of the plasma in the VASIMR experiment. The modeling is done using an improved EMIR code for RF field calculation together with particle trajectory code for plasma transport calculat ion. The simulation results correlate with experimental data on the p lasma loading and predict higher ICRH performance for a higher density plasma target. These simulations assist in optimizing the ICRF anten na so as to achieve higher VASIMR efficiency
Improved Efficiency and Throttling Range of the VX-200 Magnetoplasma Thruster
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140438/1/1.b34801.pd
From Data to Software to Science with the Rubin Observatory LSST
The Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) dataset
will dramatically alter our understanding of the Universe, from the origins of
the Solar System to the nature of dark matter and dark energy. Much of this
research will depend on the existence of robust, tested, and scalable
algorithms, software, and services. Identifying and developing such tools ahead
of time has the potential to significantly accelerate the delivery of early
science from LSST. Developing these collaboratively, and making them broadly
available, can enable more inclusive and equitable collaboration on LSST
science.
To facilitate such opportunities, a community workshop entitled "From Data to
Software to Science with the Rubin Observatory LSST" was organized by the LSST
Interdisciplinary Network for Collaboration and Computing (LINCC) and partners,
and held at the Flatiron Institute in New York, March 28-30th 2022. The
workshop included over 50 in-person attendees invited from over 300
applications. It identified seven key software areas of need: (i) scalable
cross-matching and distributed joining of catalogs, (ii) robust photometric
redshift determination, (iii) software for determination of selection
functions, (iv) frameworks for scalable time-series analyses, (v) services for
image access and reprocessing at scale, (vi) object image access (cutouts) and
analysis at scale, and (vii) scalable job execution systems.
This white paper summarizes the discussions of this workshop. It considers
the motivating science use cases, identified cross-cutting algorithms,
software, and services, their high-level technical specifications, and the
principles of inclusive collaborations needed to develop them. We provide it as
a useful roadmap of needs, as well as to spur action and collaboration between
groups and individuals looking to develop reusable software for early LSST
science.Comment: White paper from "From Data to Software to Science with the Rubin
Observatory LSST" worksho
Error Control and Mesh Optimization for High-Order Finite Element Approximation of Incompressible Viscous Flow
We discuss the use of a posteriori error estimates for highorder finite element methods during simulation of the flow of incompressible viscous fluids. The correlation between the error estimator and actual error is used as a criterion for the error analysis efficiency. We show how to use the error estimator for mesh optimization which improves computational efficiency for both steady-state and unsteady flows. The method is applied to two-dimensional problems with known analytical solutions (Jeffrey-Hamel flow) and more complex flows around a body, both in a channel and in an open domain
Accuracy Improvement in Magnetic Field Modeling for an Axisymmetric Electromagnet
This paper examines the accuracy and calculation speed for the magnetic field computation in an axisymmetric electromagnet. Different numerical techniques, based on an adaptive nonuniform grid, high order finite difference approximations, and semi-analitical calculation of boundary conditions are considered. These techniques are being applied to the modeling of the Variable Specific Impulse Magnetoplasma Rocket. For high-accuracy calculations, a fourth-order scheme offers dramatic advantages over a second order scheme. For complex physical configurations of interest in plasma propulsion, a second-order scheme with nonuniform mesh gives the best results. Also, the relative advantages of various methods are described when the speed of computation is an important consideration
First measurement of the angular coefficients in the forward region of collisions at TeV
The first study of the angular distribution of pairs produced in the forward rapidity region via the Drell-Yan reaction is presented, using data collected with the LHCb detector at a centre-of-mass energy of 13TeV, corresponding to an integrated luminosity of 5.1 . The coefficients of the five leading terms in the angular distribution are determined as a function of the dimuon transverse momentum and rapidity. The results are compared to various theoretical predictions of the -boson production mechanism and can also be used to probe transverse-momentum-dependent parton distributions within the proton
First measurement of the angular coefficients in the forward region of collisions at TeV
International audienceThe first study of the angular distribution of pairs produced in the forward rapidity region via the Drell-Yan reaction is presented, using data collected with the LHCb detector at a centre-of-mass energy of 13TeV, corresponding to an integrated luminosity of 5.1 . The coefficients of the five leading terms in the angular distribution are determined as a function of the dimuon transverse momentum and rapidity. The results are compared to various theoretical predictions of the -boson production mechanism and can also be used to probe transverse-momentum-dependent parton distributions within the proton