Physics-informed machine learning techniques for edge plasma turbulence modelling in computational theory and experiment

• URL: http://arxiv.org/abs/2205.07838v1
• Date: Mon, 16 May 2022 17:46:14 GMT
• Title: Physics-informed machine learning techniques for edge plasma turbulence modelling in computational theory and experiment
• Authors: Abhilash Mathews
• Abstract summary: Edge plasma turbulence is critical to the performance of magnetic confinement fusion devices. This thesis presents the first 2-dimensional time-dependent experimental measurements of the turbulent electron density, electron temperature, and neutral density in a fusion plasma.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: 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 partial differential equations is developed to accurately learn turbulent fields consistent with the two-fluid theory from partial observations of electron pressure. This calculation is not otherwise possible using conventional equilibrium models. With this technique, the first direct quantitative comparisons of turbulent fields between electrostatic two-fluid theory and electromagnetic gyrokinetic modelling are demonstrated with good overall agreement found in magnetized helical plasmas at low normalized pressure. To translate these computational techniques to experimental fusion plasmas, a novel method to translate brightness measurements of HeI line radiation into local plasma fluctuations is demonstrated via a newly created deep learning framework that integrates neutral transport physics and collisional radiative theory for the $3^3 D - 2^3 P$ transition in atomic helium. Using fast camera data on the Alcator C-Mod tokamak, this thesis presents the first 2-dimensional time-dependent experimental measurements of the turbulent electron density, electron temperature, and neutral density in a fusion plasma using a single spectral line. With this experimentally inferred data, initial estimates of the 2-dimensional turbulent electric field consistent with drift-reduced Braginskii theory under the framework of an axisymmetric fusion plasma with purely toroidal field are calculated. The inclusion of atomic helium effects on particle and energy sources are found to strengthen correlations between the electric field and electron pressure while broadening turbulent field amplitudes which impact ${\bf E \times B}$ flows and shearing rates.

Related papers

• Nonreciprocal recovery of electromagnetically induced transparency by wavenumber mismatch in hot atoms [0.0699049312989311]
  In a three-level atomic ladder-system, Doppler broadening limits the visibility of electromagnetically-induced transparency (EIT) when the probe and control fields are co-propagating. We show the underlying mechanism to be an avoided crossing of the states dressed by the coupling laser as a function of atomic velocities when $k_pk_c$. We investigate how the non-reciprocity scales with wavelength mismatch and show how to experimentally demonstrate the effect in a simple Rydberg-EIT system using thermal Rubidium atoms.
  arXiv  Detail & Related papers  (2024-03-03T16:11:16Z)
• Spin Current Density Functional Theory of the Quantum Spin-Hall Phase [59.50307752165016]
  We apply the spin current density functional theory to the quantum spin-Hall phase. We show that the explicit account of spin currents in the electron-electron potential of the SCDFT is key to the appearance of a Dirac cone.
  arXiv  Detail & Related papers  (2022-08-29T20:46:26Z)
• Photoinduced prethermal order parameter dynamics in the two-dimensional large-$N$ Hubbard-Heisenberg model [77.34726150561087]
  We study the microscopic dynamics of competing ordered phases in a two-dimensional correlated electron model. We simulate the light-induced transition between two competing phases.
  arXiv  Detail & Related papers  (2022-05-13T13:13:31Z)
• Deep electric field predictions by drift-reduced Braginskii theory with plasma-neutral interactions based upon experimental images of boundary turbulence [0.0]
  We present 2-dimensional turbulent electric field calculations via physics-informed deep learning. The inclusion of effects from the locally atomic helium on particle and energy sources are found to strengthen correlations between the electric field and electron pressure.
  arXiv  Detail & Related papers  (2022-04-25T14:25:55Z)
• Engineering the Radiative Dynamics of Thermalized Excitons with Metal Interfaces [58.720142291102135]
  We analyze the emission properties of excitons in TMDCs near planar metal interfaces. We find suppression or enhancement of emission relative to the point dipole case by several orders of magnitude. nanoscale optical cavities are a viable pathway to generating long-lifetime exciton states in TMDCs.
  arXiv  Detail & Related papers  (2021-10-11T19:40:24Z)
• Ab initio linear-response approach to vibro-polaritons in the cavity Born-Oppenheimer approximation [0.0]
  We study mixed vibration-photon (vibro-polariton) states of molecules based on the cavity Born-Oppenheimer approximation and quantum-electrodynamical density-functional theory. We develop an accurate model that highlights the consistent treatment of cavity coupled electrons in the vibrational strong coupling regime.
  arXiv  Detail & Related papers  (2021-08-26T03:12:21Z)
• Turbulent field fluctuations in gyrokinetic and fluid plasmas [0.0]
  Key uncertainty in the design and development of magnetic confinement fusion energy reactors is predicting edge plasma turbulence. Drift-reduced Braginskii two-fluid theory is one such set of reduced equations that has for decades simulated boundary plasmas in experiment. We demonstrate the first ever direct quantitative comparisons of turbulent field fluctuations between electrostatic two-fluid theory and electromagnetic gyrokinetic modelling.
  arXiv  Detail & Related papers  (2021-07-20T19:50:30Z)
• Relativistic aspects of orbital and magnetic anisotropies in the chemical bonding and structure of lanthanide molecules [60.17174832243075]
  We study the electronic and ro-vibrational states of heavy homonuclear lanthanide Er2 and Tm2 molecules by applying state-of-the-art relativistic methods. We were able to obtain reliable spin-orbit and correlation-induced splittings between the 91 Er2 and 36 Tm2 electronic potentials dissociating to two ground-state atoms.
  arXiv  Detail & Related papers  (2021-07-06T15:34:00Z)
• BIGDML: Towards Exact Machine Learning Force Fields for Materials [55.944221055171276]
  Machine-learning force fields (MLFF) should be accurate, computationally and data efficient, and applicable to molecules, materials, and interfaces thereof. Here, we introduce the Bravais-Inspired Gradient-Domain Machine Learning approach and demonstrate its ability to construct reliable force fields using a training set with just 10-200 atoms.
  arXiv  Detail & Related papers  (2021-06-08T10:14:57Z)
• Semiconductor nanodevices as a probe of strong electron correlations [0.0]
  We look at how tunnelling spectroscopy can be used as the experimental tool of choice for probing correlation and interaction effects in 1D electron systems. We present some early experimental results obtained using tunnelling devices and how they contributed to the decisive observation of both spin-charge separation and power-law behaviour. In the second half of the chapter we introduce two nonlinear models that are counterparts to the TLL theory, known as the mobile-impurity and the mode-hierarchy pictures.
  arXiv  Detail & Related papers  (2021-05-25T16:47:07Z)
• A multiconfigurational study of the negatively charged nitrogen-vacancy center in diamond [55.58269472099399]
  Deep defects in wide band gap semiconductors have emerged as leading qubit candidates for realizing quantum sensing and information applications. Here we show that unlike single-particle treatments, the multiconfigurational quantum chemistry methods, traditionally reserved for atoms/molecules, accurately describe the many-body characteristics of the electronic states of these defect centers.
  arXiv  Detail & Related papers  (2020-08-24T01:49:54Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.