{"id":554,"date":"2020-01-08T15:43:14","date_gmt":"2020-01-08T15:43:14","guid":{"rendered":"http:\/\/192.168.1.80\/?page_id=554"},"modified":"2024-08-29T21:21:17","modified_gmt":"2024-08-29T21:21:17","slug":"computing","status":"publish","type":"page","link":"https:\/\/verscharen.com\/?page_id=554","title":{"rendered":"Numerics and Computing"},"content":{"rendered":"\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-122 alignright\" src=\"https:\/\/verscharen.com\/wp-content\/uploads\/2022\/01\/current_density.png\" alt=\"\" width=\"260\" height=\"260\">My research often exploits computer simulations and numerical tools. We use fluid and kinetic plasma simulations to model turbulence, kinetic instabilities, magnetic reconnection, and the global evolution of plasma systems. Some of these numerical methods describe the plasma as a highly conducting fluid (magnetohydrodynamics), others treat the plasma as a collection of individual particles (particle-in-cell). <br>\nOur simulation work based on particle-in-cell simulations of turbulence has led to a number of press releases and articles: <\/p>\n<ul><li><a href=\"https:\/\/www.eltiempo.com\/vida\/ciencia\/un-colombiano-lidera-equipo-que-busca-revelar-secretos-del-plasma-588363\" target=\"_blank\" rel=\"noopener noreferrer\">El Tiempo: Un colombiano lidera equipo que busca revelar secretos del plasma (in Spanish)<\/a><\/li>\n<li><a href=\"https:\/\/www.dailymail.co.uk\/sciencetech\/article-9575863\/Solar-winds-stay-hot-magnetic-connections-form-turbulence-study-reveals.html\" target=\"_blank\" rel=\"noopener noreferrer\">Daily Mail online: Why solar winds are 10 TIMES hotter than expected when they hit Earth: Streams stay so hot because of magnetic connections that form in the turbulence, study reveals<\/a><\/li>\n<li><a href=\"https:\/\/www.ukri.org\/news\/supercomputer-simulations-unlock-an-old-space-weather-puzzle\" target=\"_blank\" rel=\"noopener noreferrer\">UKRI: Supercomputer simulations unlock an old space weather puzzle<\/a><\/li>\n<li><a href=\"https:\/\/www.ucl.ac.uk\/news\/2021\/may\/supercomputer-simulations-unlock-space-weather-puzzle\" target=\"_blank\" rel=\"noopener noreferrer\">UCL: Supercomputer simulations unlock space weather puzzle<\/a><\/li>\n<\/ul>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-122 alignleft\" src=\"https:\/\/verscharen.com\/wp-content\/uploads\/2017\/01\/logo2.png\" alt=\"\" width=\"213\" height=\"145\">One of my current projects is the application of our computer code ALPS, which stands for Arbitrary Linear Plasma Solver. ALPS is a numerical solver for the full hot-plasma dispersion relation in a plasma with arbitrary background distribution functions. The numerical code determines the behaviour of kinetic plasma waves including relativistic effects. A particular strength of the code is that it can use velocity distribution functions measured by spacecraft and analyser their stability directly. More details can be found on&nbsp;<a href=\"http:\/\/alps.space\" target=\"_blank\" rel=\"noopener noreferrer\">http:\/\/alps.space<\/a>. The ALPS code is publicly available at <a href=\"https:\/\/github.com\/danielver02\/ALPS\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/github.com\/danielver02\/ALPS<\/a>, and the code paper can be found <a href=\"https:\/\/www.cambridge.org\/core\/journals\/journal-of-plasma-physics\/article\/alps-the-arbitrary-linear-plasma-solver\/B05A3FFAA8875A37A1BDB128DEB58EA1\" target=\"_blank\" rel=\"noopener noreferrer\">here<\/a>. <\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-122 alignright\" src=\"https:\/\/verscharen.com\/wp-content\/uploads\/2018\/04\/NHDS_logo.png\" alt=\"\" width=\"213\" height=\"115\">Our solver NHDS (The New Hampshire Dispersion Relation Solver) calculates the linear hot-plasma dispersion relation in a plasma consisting of drifting bi-Maxwellians. The code is publicly available at <a href=\"https:\/\/github.com\/danielver02\/NHDS\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/github.com\/danielver02\/NHDS<\/a>, and the code paper can be found <a href=\"http:\/\/iopscience.iop.org\/article\/10.3847\/2515-5172\/aabfe3\" target=\"_blank\" rel=\"noopener noreferrer\">here<\/a>.<br>\nNHDS has been used in many studies to compare predictions from linear theory with spacecraft observations and simulations. One prominent example of this work has been featured in the following media articles:\n<ul><li><a href=\"https:\/\/www.ucl.ac.uk\/news\/2022\/dec\/how-magnetic-waves-interact-earths-bubble\" target=\"_blank\" rel=\"noopener noreferrer\">UCL: How magnetic waves interact with Earth&#8217;s bubble<\/a><\/li>\n<li><a href=\"https:\/\/www.helsinki.fi\/en\/news\/space\/new-study-models-transmission-foreshock-waves-towards-earth\" target=\"_blank\" rel=\"noopener noreferrer\">U Helsinki: New study models the transmission of foreshock waves towards Earth<\/a><\/li>\n<li><a href=\"https:\/\/www.issibern.ch\/from-teams-earths-bow-shock\/\" target=\"_blank\" rel=\"noopener noreferrer\">ISSI: Transmission of Foreshock Waves Through Earth&#8217;s Bow Shock<\/a><\/li>\n<\/ul><\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-460\" src=\"https:\/\/verscharen.com\/wp-content\/uploads\/2019\/07\/logo.png\" alt=\"\" width=\"320\" height=\"68\">HolmMHD is a versatile numerical code that solves the nonlinear set of equations of isotropic, polytropic, ideal magnetohydrodynamics (MHD) on a Cartesian grid in three dimensions. It uses a hybrid spatial discretisation based on a fourth-order central scheme and the Rusanov scheme, which are mixed through a min-mod flux limiter. <img loading=\"lazy\" decoding=\"async\" class=\"alignright size-full wp-image-464\" src=\"https:\/\/verscharen.com\/wp-content\/uploads\/2019\/07\/output.gif\" alt=\"\" width=\"325\" height=\"190\"><br>The code performs well on a range of benchmark problems such as a spherical hydro-blast wave, the Orszag-Tang vortex, Alfv\u00e9n waves in one and three dimensions, the MHD aligned rotator, an isotropic three-dimensional decaying-turbulence setup, and the Kelvin-Helmholtz instability (shown on the right-hand side). The code is publicly available at <a href=\"https:\/\/github.com\/danielver02\/HolmMHD\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/github.com\/danielver02\/HolmMHD<\/a>, and the code paper can be found <a href=\"https:\/\/iopscience.iop.org\/article\/10.3847\/2515-5172\/ab30c8\" target=\"_blank\" rel=\"noopener noreferrer\">here<\/a>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><br> <\/p>\n","protected":false},"excerpt":{"rendered":"<p>My research often exploits computer simulations and numerical tools. We use fluid and kinetic plasma simulations to model turbulence, kinetic instabilities, magnetic reconnection, and the global evolution of plasma systems. Some of these numerical methods describe the plasma as a highly conducting fluid (magnetohydrodynamics), others treat the plasma as a collection of individual particles (particle-in-cell). [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-554","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/verscharen.com\/index.php?rest_route=\/wp\/v2\/pages\/554","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/verscharen.com\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/verscharen.com\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/verscharen.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/verscharen.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=554"}],"version-history":[{"count":21,"href":"https:\/\/verscharen.com\/index.php?rest_route=\/wp\/v2\/pages\/554\/revisions"}],"predecessor-version":[{"id":1257,"href":"https:\/\/verscharen.com\/index.php?rest_route=\/wp\/v2\/pages\/554\/revisions\/1257"}],"wp:attachment":[{"href":"https:\/\/verscharen.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=554"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}