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Quantitative inversion algorithms allow for the reconstruction of electrical properties (such as permittivity, and conductivity) for every point in a scene. However, they are challenging to use on measured datasets due to the need to know…

Signal Processing · Electrical Eng. & Systems 2025-05-15 Zacharie Idriss , Raghu Raj

In this work we deal with parametric inverse problems, which consist in recovering a finite number of parameters describing the structure of an unknown object, from indirect measurements. State-of-the-art methods for approximating a…

Numerical Analysis · Mathematics 2021-12-22 Paolo Massa , Sara Garbarino , Federico Benvenuto

We have calculated the photonic band structures of metallic inverse opals and of periodic linear chains of spherical pores in a metallic host, below a plasma frequency $\omega_{\text{p}}$. In both cases, we use a tight-binding…

Mesoscale and Nanoscale Physics · Physics 2011-11-11 Kwangmoo Kim , D. Stroud

Full waveform inversion (FWI) commonly stands for the state-of-the-art approach for imaging subsurface structures and physical parameters, however, its implementation usually faces great challenges, such as building a good initial model to…

Geophysics · Physics 2023-04-05 Jian Sun , Kristopher Innanen

In this paper we present a new multilevel quasi-interpolation algorithm for smooth periodic functions using scaled Gaussians as basis functions. Recent research in this area has focussed upon implementations using basis function with finite…

Numerical Analysis · Mathematics 2017-03-14 Simon Hubbert , Jeremy Levesley

Edge plasma turbulence is critical to the performance of magnetic confinement fusion devices. Towards better understanding edge turbulence in both theory and experiment, a custom-built physics-informed deep learning framework constrained by…

Plasma Physics · Physics 2022-05-17 Abhilash Mathews

Radiation hydrodynamical transport of ionization fronts in the next generation of cosmological reionization simulations holds the promise of predicting UV escape fractions from first principles as well as investigating the role of…

Astrophysics · Physics 2009-11-11 Daniel J. Whalen , Michael L. Norman

In the context of global gyrokinetic simulations of turbulence using a Particle-In-Cell framework, verifying the delta-f assumption with a fixed background distribution becomes challenging when determining quasi-steady state profiles…

We perform experiments in the Large Plasma Device (LAPD) at the University of California, Los Angeles, studying how different end-electrode biasing schemes modify the radial potential profile in the machine. We impose biasing profiles of…

Plasma Physics · Physics 2024-11-20 R. Gueroult , S. K. P. Tripathi , F. Gaboriau , T. R. Look , N. J. Fisch

Machine learning models are exceptionally effective in capturing complex non-linear relationships of high-dimensional datasets and making accurate predictions. However, their intrinsic ``black-box'' nature makes it difficult to interpret…

Plasma Physics · Physics 2024-07-29 Tadas Pyragius , Cary Colgan , Hazel Lowe , Filip Janky , Matteo Fontana , Yichen Cai , Graham Naylor

In this article, we present a detailed characterisation of a multicusp-assisted inductively coupled RF plasma source for plasma immersion ion implantation (PIII). Using laser-induced fluorescence (LIF) and RF-compensated Langmuir probe…

Aiming to correctly restore the redshifted 21 cm signals emitted by the neutral hydrogen during the cosmic reionization processes, we re-examine the separation approaches based on the quadratic polynomial fitting technique in frequency…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Jingying Wang , Haiguang Xu , Tao An , Junhua Gu , Xueying Guo , Weitian Li , Yu Wang , Chengze Liu , Olivier Martineau-Huynh , Xiang-Ping Wu

Hyperfine-structures of highly charged ions (HCIs) are favourable spectroscopic targets for exploring fundamental physics as well as nuclear properties. Recent proposals of HCI atomic clocks highlight their importance, especially for…

X-ray spectral fitting of astronomical sources requires convolving the intrinsic spectrum or model with the instrumental response. Standard forward modeling techniques have proven success in recovering the underlying physical parameters in…

Instrumentation and Methods for Astrophysics · Physics 2021-05-21 Carter Lee Rhea , Julie Hlavacek-Larrondo , Ralph Kraft , Akos Bogdan , Rudy Geelen

We are concerned with high-fidelity subsurface imaging of the soil, which commonly arises in geotechnical site characterization and geophysical explorations. Specifically, we attempt to image the spatial distribution of the Lame parameters…

Numerical Analysis · Mathematics 2015-10-28 Arash Fathi , Loukas F. Kallivokas , Babak Poursartip

We propose a scheme for imaging periodic surfaces using a superlens. By employing an inverse scattering model and the transformed field expansion method, we derive an approximate reconstruction formula for the surface profile, assuming…

Numerical Analysis · Mathematics 2024-03-05 Peijun Li , Yuliang Wang

Eikonal, or ray tracing, methods are commonly used to estimate the propagation of radio frequency fields in plasmas. While the information gained from the rays is quite useful, an approximate solution for the fields would also be valuable,…

Plasma Physics · Physics 2010-05-20 A. S. Richardson , P. T. Bonoli , J. C. Wright

This paper reports an innovative concept of ``plasma fibre" using bright-core helicon plasma, inspired by its spatial and spectral similarities to the well-known optical fibre. Theoretical analyses are presented for both ideal case of…

The consistency of time--distance inversions for horizontal components of the plasma flow on supergranular scales in the upper solar convection zone is checked by comparing the results derived using two k--\omega filtering procedures --…

Solar and Stellar Astrophysics · Physics 2015-06-16 Michal Svanda

In this paper, the analytical form of the quasilinear diffusion coefficients is modified from the Kennel-Engelmann diffusion coefficients to guarantee the positive definiteness of its bounce average in a toroidal geometry. By evaluating the…

Plasma Physics · Physics 2018-01-17 Jungpyo Lee , David Smithe , John Wright , Paul Bonoli