Riva, Fabio Matteo Milanese, Lucio Ricci, Paolo 2017 To reduce the computational cost of the uncertainty propagation analysis, which is used to study the impact of input parameter variations on the results of a simulation, a general and simple to apply methodology based on decomposing the solution to the model equations in terms of Chebyshev polynomials is discussed. This methodology, based on the work by Scheffel [Am. J. Comput. Math. 2, 173–193 (2012)], approximates the model equation solution with a semi-analytic expression that depends explicitly on time, spatial coordinates, and input parameters. By employing a weighted residual method, a set of nonlinear algebraic equations for the coefficients appearing in the Chebyshev decomposition is then obtained. The methodology is applied to a two-dimensional Braginskii model used to simulate plasma turbulence in basic plasma physics experiments and in the scrape-off layer of tokamaks, in order to study the impact on the simulation results of the input parameter that describes the parallel losses. The uncertainty that characterizes the time-averaged density gradient lengths, time-averaged densities, and fluctuation density level are evaluated. A reasonable estimate of the uncertainty of these distributions can be obtained with a single reduced-cost simulation. application/pdf https://susi.usi.ch/global/documents/337020 https://n2t.net/ark:/12658/srd1337020 https://susi.usi.ch/documents/337020/files/Uncertanty propagation - submitted.pdf eng info:eu-repo/semantics/altIdentifier/issn/1070-664X, 1089-7674 info:eu-repo/semantics/altIdentifier/doi/10.1063/1.4996445 info:eu-repo/semantics/altIdentifier/ark/12658/srd1337020 info:eu-repo/semantics/openAccess License undefined Physics of Plasmas. - 2017, vol. 24, no. 10, p. 102302 Finite difference methods Operator theory Spectral methods Sols Plasma dynamics Plasma physics Plasma properties and parameters Plasma transport properties Plasma turbulence Tokamaks info:eu-repo/classification/udc/53 Uncertainty propagation by using spectral methods : a practical application to a two-dimensional turbulence fluid model http://purl.org/coar/resource_type/c_6501