'+pages+''); $('.stream > div:odd').addClass('bgr_color'); updateHeight('#history'); }); window.activateTabArea = ensure(function(tab, areas){ var parsed = false; var parts = (areas || '').split('/'); window.fsonload = $.inArray('fs', parts) >= 0; if(fsonload){ parts.splice(parts.indexOf('fs'), 1); } var replayMode = false; if($.inArray('replay', parts)>=0){ replayMode = 'replay'; } var noSoundMode = false; if($.inArray('nosound', parts)>=0){ noSoundMode = 'nosound'; } if($.inArray('ns', parts)>=0){ noSoundMode = 'ns'; } var previewMode = null; if($.inArray('p', parts)>=0){ previewMode = 'p'; } if($.inArray('preview', parts)>=0){ previewMode = 'preview'; } if($.inArray('repeat', parts)>=0){ replayMode = 'repeat'; } if($.inArray('r', parts)>=0 || $.inArray('ro', parts)>=0){ replayMode = 'r'; } if(replayMode){ parts.splice(parts.indexOf(replayMode), 1); } if(noSoundMode){ parts.splice(parts.indexOf(noSoundMode), 1); } if(previewMode){ parts.splice(parts.indexOf(previewMode), 1); } if(previewMode){ if(!parts.length){ parts = ['1-14', '999:59']; } } var area = parts[0]; if(tab == 'history' && false){ var page = parseInt(area || '1') || 1; $.ajax({ url: 'https://login.wn.com/recent/json/?pp='+history_pp+'&skip='+history_pp*(page-1), dataType: 'jsonp', success: function(response){ $ensure(function(){ renderHistory(response, page); }); } }); return true; } if(tab == 'global_history' && false){ var page = parseInt(area || '1') || 1; globalHistory.fetchStream(page, '', function(){ updateHeight('#global_history'); }); return true; } if(tab == 'my_playlists' && false){ var page = parseInt(area || '1') || 1; myPlaylists.fetchStream(page, '', function(){ updateHeight('#my_playlists'); }); return true; } if(tab == 'my_videos' && false){ var page = parseInt(area || '1') || 1; myVideos.fetchStream(page, '', function(){ updateHeight('#my_videos'); }); return true; } if(tab == 'related_sites' && areas && matchPosition(areas)){ var seconds = parsePosition(areas); scrollRelated(seconds); return false; } if(matchPosition(area) || matchAction(area)){ parts.unshift('1'); area = parts[0]; } if(tab == 'expand' && area && area.match(/\d+/)) { var num = parseInt(area); if(num < 100){ //FIX ME. Load news page with ajax here } else if(num > 1900){ //FIX ME. Load timeline page with ajax here } } else if(tab.match(/^playlist\d+$/)){ var playerId = parseInt(tab.substring(8)); var vp = videoplayers[playerId]; window.descriptionsholder = $('.descriptionsplace'); if(!vp) return; // why? no player? if(replayMode){ $('.replaycurrent'+playerId).attr('checked', true); vp.setReplayCurrent(true); } var playQueue = []; window.playQueue = playQueue; var playQueuePosition = 0; var playShouldStart = null; var playShouldStop = null; var parseList = function(x){ var items = x.split(/;|,/g); var results = []; for (i in items){ try{ var action = parseAction(vp, items[i]); if(!action.video){ if(window.console && console.log) console.log("Warning: No video for queued entry: " + items[i]); }else{ results.push(action); } }catch(e){ if(window.console && console.log) console.log("Warning: Can''t parse queue entry: " + items[i]); } } return results; }; var scrollToPlaylistPosition = function(vp){ var ppos = vp.getPlaylistPosition(); var el = vp.playlistContainer.find('>li').eq(ppos); var par = el.closest('.playlist_scrollarea'); par.scrollTop(el.offset().top-par.height()/2); } var updateVolumeState = function(){ if(noSoundMode){ if(noSoundMode == 'turn-on'){ clog("Sound is on, vsid="+vp.vsid); vp.setVolumeUnMute(); noSoundMode = false; }else{ clog("Sound is off, vsid="+vp.vsid); vp.setVolumeMute(); noSoundMode = 'turn-on'; } } } var playQueueUpdate = function(){ var playPosition = playQueue[playQueuePosition]; vp.playFromPlaylist(playPosition.video); scrollToPlaylistPosition(vp); playShouldStart = playPosition.start; playShouldStop = playPosition.stop; }; var playQueueAdvancePosition = function(){ clog("Advancing play position..."); playQueuePosition ++; while(playQueuePosition < playQueue.length && !playQueue[playQueuePosition].video){ playQueuePosition ++; } if(playQueuePosition < playQueue.length){ playQueueUpdate(); }else if(vp.getReplayCurrent()){ playQueuePosition = 0; playQueueUpdate(); vp.seekTo(playShouldStart); vp.playVideo(); }else{ vp.pauseVideo(); playShouldStop = null; playShouldStart = null; } }; function loadMoreVideos(playerId, vp, start, finish, callback){ var playlistInfo = playlists[playerId-1]; if(playlistInfo.loading >= finish) return; playlistInfo.loading = finish; $.ajax({ url: '/api/upge/cheetah-photo-search/query_videos2', dataType: 'json', data: { query: playlistInfo.query, orderby: playlistInfo.orderby, start: start, count: finish-start }, success: function(response){ var pl = vp.getPlaylist().slice(0); pl.push.apply(pl, response); vp.setPlaylist(pl); callback(); } }); } if(parts.length == 1 && matchDash(parts[0])){ var pl = vp.getActualPlaylist(); var vids = parseDash(parts[0]); parts = []; for(var i = 0; i < vids.length; i++){ playQueue.push({ 'video': pl[vids[i]-1], 'start': 0, 'stop': null }) } if(vids.length){ if(vids[vids.length-1]-1>=pl.length){ loadMoreVideos(playerId, vp, pl.length, vids[vids.length-1], function(){ if(fsonload){ activateTabArea(tab, parts[0]+'/fs'); }else{ activateTabArea(tab, parts[0]); } var pls = vp.getPlaylist(); vp.playFromPlaylist(pls[pls.length-1]); vp.playVideo(); scrollToPlaylistPosition(vp); }); return true; } } if(playQueue){ playQueueUpdate(); vp.playVideo(); parsed = true; playShouldStart = 0; } } if(previewMode){ var vids = []; var dur = 0; var pl = vp.getActualPlaylist(); area = parts[0]; if(parts.length == 1 && matchPosition(parts[0])){ vids = parseDash('1-'+pl.length); dur = parsePosition(parts[0]); parts = []; }else if(parts.length == 1 && matchDash(parts[0])){ vids = parseDash(parts[0]); dur = parsePosition("999:59"); parts = []; } if(parts.length == 2 && matchDash(parts[0]) && matchPosition(parts[1])){ vids = parseDash(parts[0]); dur = parsePosition(parts[1]); parts = []; } for(var i = 0; i < vids.length; i++){ playQueue.push({ 'video': pl[vids[i]-1], 'start': 0, 'stop': dur }) } if(playQueue){ playQueueUpdate(); vp.playVideo(); parsed = true; } } if(parts.length>1){ for(var i = 0; i < parts.length; i++){ var sel = findMatchingVideo(vp, parts[i]); if(sel){ playQueue.push({ 'video': sel, 'start': 0, 'stop': null }) } } if(playQueue){ playQueueUpdate(); vp.playVideo(); parsed = true; } }else if(area){ var sel = findMatchingVideo(vp, area); if(sel){ vp.playFromPlaylist(sel); playShouldStart = 0; parsed = true; } } if(fsonload || replayMode){ playShouldStart = 0; } if(document.location.search.match('at=|queue=')){ var opts = document.location.search.replace(/^\?/,'').split(/&/g); for(var o in opts){ if(opts[o].match(/^at=(\d+:)?(\d+:)?\d+$/)){ playShouldStart = parsePosition(opts[o].substr(3)) } if(opts[o].match(/^queue=/)){ playQueue = parseList(opts[o].substr(6)); if(playQueue){ playQueuePosition = 0; playQueueUpdate(); } } } } if(matchPosition(parts[1])){ playShouldStart = parsePosition(parts[1]); parsed = true; } if(matchAction(parts[1])){ var action = parseAction(vp, area+'/'+parts[1]); playShouldStart = action.start; playShouldStop = action.stop; parsed = true; } if(playShouldStart !== null && !playQueue.length){ playQueue.push({ video: vp.getCurrentVideo(), start: playShouldStart, stop: playShouldStop }); } if(playShouldStart != null){ setInterval(function(){ if(playShouldStop && vp.currentPlayer && vp.currentPlayer.getCurrentTime() > playShouldStop){ playShouldStop = null; if(vp.getCurrentVideo() == playQueue[playQueuePosition].video){ playQueueAdvancePosition(); }else{ playShouldStart = null; } } }, 500); vp.playerContainer.bind('videoplayer.player.statechange', function(e, state){ if(state == 'ended'){ // advance to the next video playQueueAdvancePosition(); } }); vp.playerContainer.bind('videoplayer.player.readychange', function(e, state){ if(state){ updateVolumeState(); if(playShouldStart !== null){ vp.seekTo(playShouldStart); playShouldStart = null; }else{ playShouldStop = null; // someone started other video, stop playing from playQueue } } if(fsonload) { triggerFullscreen(playerId); fsonload = false; } }); } } else if(tab.match(/^wiki\d+$/)){ if(firstTimeActivate){ load_wiki($('#'+tab), function(){ if(area){ var areaNode = $('#'+area); if(areaNode.length>0){ $('html, body').scrollTop(areaNode.offset().top + 10); return true; } } }); } } return parsed; }) window.activateTab = ensure(function(tab, area){ window.activeArea = null; if(tab == 'import_videos'){ if(area){ import_videos(area); }else{ start_import(); } return true; } if(tab == 'chat'){ update_chat_position($('.chat').eq(0)); window.activeArea = 'chat'; jQuery('.tabtrigger').offscreentabs('activateTab', 'chat'); return true; } if(tab in rev_names){ tab = rev_names[tab]; } if(tab.match(':')){ return false; } var sup = $('ul li a[id=#'+tab+']'); if(sup && sup.length>0){ window.activeArea = area; sup.first().click(); if(!window.activateTabArea(tab, area)){ window.activeArea = null; } window.activeArea = null; return true; }else{ var have_tabs = $('#playlist_menu li').length; if(tab.match(/^playlists?\d+$/)){ var to_add = +tab.substring(8).replace(/^s/,'')-have_tabs; if(to_add>0 && have_tabs){ add_more_videos(to_add); return true; } } } return false; }); window.currentPath = ensure(function(){ return window.lastHistory.replace(basepath, '').split('?')[0]; }); window.main_tab = window.main_tab || 'videos'; window.addHistory = ensure(function(path){ if(window.console && console.log) console.log("Adding to history: "+path); if(window.history && history.replaceState && document.location.hostname.match(/^(youtube\.)?(\w{2,3}\.)?wn\.com$/)){ if(path == main_tab || path == main_tab+'/' || path == '' || path == '/') { path = basepath; } else if( path.match('^'+main_tab+'/') ){ path = basepath + '/' + path.replace(main_tab+'/', '').replace('--','/'); } else { path = basepath + '/' + path.replace('--','/'); } if(document.location.search){ path += document.location.search; } if(window.lastHistory) { history.pushState(null, null, path); } else if(window.lastHistory != path){ history.replaceState(null, null, path); window.lastHistory = path; } } else{ path = path.replace('--','/'); if(path == main_tab || path == main_tab+'/' || path == '' || path == '/') { path = ''; } if(window.lastHistory != '/'+path){ window.location.hash = path? '/'+path : ''; window.lastHistory = '/'+path; } } }); $('.tabtrigger li a').live('click', ensure(function() { var tab = $(this).attr('id'); if(tab.substring(0,1) == '#'){ var name = tab.substring(1); if(name in menu_names){ name = menu_names[name][0]; } realTab = rev_names[name]; $('#'+realTab).show(); if(window.console && console.log) console.log("Triggering tab: "+name+(window.activeArea?" activeArea="+window.activeArea:'')); var path = name; if(window.activeArea){ path = path + '/' + window.activeArea; } if(tab.match(/#playlist\d+/) || tab.match(/#details\d+/)){ $('.multiple-playlists').show(); $('.related_playlist').show(); $('.longest_videos_playlist').show(); }else { $('.multiple-playlists').hide(); $('.related_playlist').hide(); $('.longest_videos_playlist').hide(); } // start the related script only when the tab is on screen showing if (tab.match(/related_sites/)) { if (mc) { mc.startCredits(); } } window.activeTab = realTab; addHistory(path); setTimeout(ensure(function(){ if(tab.match(/language--/)){ $('.tabtrigger').offscreentabs('activateTab', 'language'); } if(tab.match(/weather/)) { $('.tabtrigger').offscreentabs('activateTab', 'weather'); loadContinent(); } updateMenus(tab); updateHeight(); }), 10); } return false; })); }); -->

Alfvén wave

In plasma physics, an Alfvén wave, named after Hannes Alfvén, is a type of magnetohydrodynamic wave in which ions oscillate in response to a restoring force provided by an effective tension on the magnetic field lines.

Definition

An Alfvén wave in a plasma is a low-frequency (compared to the ion cyclotron frequency) travelling oscillation of the ions and the magnetic field. The ion mass density provides the inertia and the magnetic field line tension provides the restoring force.

The wave propagates in the direction of the magnetic field, although waves exist at oblique incidence and smoothly change into the magnetosonic wave when the propagation is perpendicular to the magnetic field.

The motion of the ions and the perturbation of the magnetic field are in the same direction and transverse to the direction of propagation. The wave is dispersionless.

Alfvén velocity

The low-frequency relative permittivity \epsilon\, of a magnetized plasma is given by

where B\, is the magnetic field strength, c\, is the speed of light, \mu_0\, is the permeability of the vacuum, and \rho = \Sigma n_s m_s\, is the total mass density of the charged plasma particles. Here, s\, goes over all plasma species, both electrons and (few types of) ions.

Podcasts:

  • Typical Alfvén Waves

    In a typical Alfvén wave, the particles (yellow) move freely along the magnetic field lines (blue). Credit: NASA Goddard's Scientific Visualization Studio/Tom Bridgman, data visualizer Related story: https://www.nasa.gov/feature/goddard/2017/nasa-observations-reshape-basic-plasma-wave-physics/

    published: 31 Mar 2017
  • Alfvén Waves: The Hidden Force Powering Solar Wind | New Discovery by ESA & NASA

    Alfvén Waves: The Hidden Force Powering Solar Wind | New Discovery by ESA & NASA Discover the groundbreaking discovery of Alfvén waves by ESA's Solar Orbiter and NASA's Parker Solar Probe, revealing how magnetic waves fuel and accelerate the solar wind. This new research explains the mystery behind the high-speed solar wind and its effects on the solar system, shedding light on phenomena that extend to other stars as well. Learn about the role of switchbacks and how this data helps us understand our Sun like never before. Make sure to like, share, and subscribe for more amazing content! https://www.youtube.com/@ScienceMaters11?sub_confirmation=1 🔗 Check out our other videos: Monn dust into water: https://youtu.be/WDjNEfuMZTY Shocking Discoveries Beyond Pluto: https://youtu.be/hlg51Z...

    published: 29 Sep 2024
  • Alfven wave

    I have been interested in a spectacular branch of physics, electric gas discharge, for a long time. In the tubes I have made, I observed this interesting, unconventional form of discharge in 1995. The regular spiral shape is formed in a very narrow parameter range. There are only guesses as why the plasma filament takes this regular form. In this video you can see one of my experiment with gas discharge. This tube has the following parameters.: Tube length: 800 mm Tube diameter: 26 mm Electrode distance: 720 mm Electrode: carbon Gas: air Tube pressure: 40 Torr Drive: HVDC #alfven #alfvenwave #mhd #plasmawave #plasma #gasdischarge

    published: 01 Nov 2022
  • Alfvén wave Meaning

    Video shows what Alfvén wave means. A hydromagnetic shear wave in a charged plasma.. Alfvén wave Meaning. How to pronounce, definition audio dictionary. How to say Alfvén wave. Powered by MaryTTS, Wiktionary

    published: 28 Apr 2015
  • Lecture 10 - Electromagnetic waves in a plasma, ordinary wave, extraordinary wave, cutoff, resonance

    Electromagnetic waves in a plasma, ordinary wave, extraordinary wave, cutoff, resonance, Alfven wave. Lecturer: Joe Khachan from the School of Physics, The University of Sydney https://sydney.edu.au/science/schools/school-of-physics.html

    published: 18 May 2017
  • Kinetic Alfvén Waves

    In a kinetic Alfvén wave, some particles become trapped in the weak spots of the wave’s magnetic field and ride along with the wave as it moves through space. Credit: NASA Goddard's Scientific Visualization Studio/Tom Bridgman, data visualizer Related story: https://www.nasa.gov/feature/goddard/2017/nasa-observations-reshape-basic-plasma-wave-physics/

    published: 31 Mar 2017
  • mod11lec55 - Magnetohydrodynamics (MHD) : Waves in MHD - Alfven waves

    Derivation of the sound speed - recap, formal derivation of Alfven speed using perturbations in magnetized fluid

    published: 08 Jun 2021
  • Alfvén Wave

    Provided to YouTube by Routenote Alfvén Wave · sakanaxbt · sakana xbt Plasmaphysics ℗ sakanaxbt Released on: 2024-09-18 Auto-generated by YouTube.

    published: 04 Oct 2024
  • Alfven wave and equation for propagation of alfven wave #plasmaphysics #b.sc.part3physics

    #alfvenwave #equation for propagation of alfven wave and formula for alfven speed #v.v.i. #lecture5 #plasmaphysics #b.sc.part3physicshonours #m.sc.physics semester2 [correction : In the denominator of R.H.S. of equation 9, read or write z in place of t. Sorry for this inconvenience. Although equation 9 is not used further in this topic or video] Abhay Kumar Physics Quantum Classes

    published: 05 Feb 2023
Typical Alfvén Waves
0:18

Typical Alfvén Waves

  • Order:
  • Duration: 0:18
  • Uploaded Date: 31 Mar 2017
  • views: 16014
In a typical Alfvén wave, the particles (yellow) move freely along the magnetic field lines (blue). Credit: NASA Goddard's Scientific Visualization Studio/Tom Bridgman, data visualizer Related story: https://www.nasa.gov/feature/goddard/2017/nasa-observations-reshape-basic-plasma-wave-physics/
https://wn.com/Typical_Alfvén_Waves
Alfvén Waves: The Hidden Force Powering Solar Wind | New Discovery by ESA & NASA
3:47

Alfvén Waves: The Hidden Force Powering Solar Wind | New Discovery by ESA & NASA

  • Order:
  • Duration: 3:47
  • Uploaded Date: 29 Sep 2024
  • views: 49
Alfvén Waves: The Hidden Force Powering Solar Wind | New Discovery by ESA & NASA Discover the groundbreaking discovery of Alfvén waves by ESA's Solar Orbiter and NASA's Parker Solar Probe, revealing how magnetic waves fuel and accelerate the solar wind. This new research explains the mystery behind the high-speed solar wind and its effects on the solar system, shedding light on phenomena that extend to other stars as well. Learn about the role of switchbacks and how this data helps us understand our Sun like never before. Make sure to like, share, and subscribe for more amazing content! https://www.youtube.com/@ScienceMaters11?sub_confirmation=1 🔗 Check out our other videos: Monn dust into water: https://youtu.be/WDjNEfuMZTY Shocking Discoveries Beyond Pluto: https://youtu.be/hlg51ZEy7AU Discovery of Big Ring of Galaxies: https://youtu.be/5ETQSlRvQl4 Will Asteroid Apophis Hit Earth? https://youtu.be/VVm4LB8ReD8 SPACE And TIME Don't Actually Exist: https://youtu.be/gjzCEMOOAQQ Mystery of Area 51: https://youtu.be/0Lo3yIKqoak Black Hole Could be Bigger Than the Universe: https://youtu.be/o3X9WOcvVN8 Is Time Travel Possible?: https://youtu.be/hPBkG5rIatM What Was There Before the Big Bang?: https://youtu.be/klXGBAHw3tY 5 Weird Theories About Space: https://youtu.be/CnGRbbCPsRw Brightest Star “Sirius”: https://youtu.be/S8Vwnke6zuU Unexplained Mysteries of the Universe: https://youtu.be/3EF4RExjDz8 Dyson Sphere and Discovery of Alien Life: https://youtu.be/lxd0r5sDCMQ At What Distance A Supernova Explosion Would Trigger Mass Extinction? https://youtu.be/ZMLJ_yVZ5Kc Could Humans Survive the Dinosaur-Killing Asteroid? https://youtu.be/zT8tzQPGEaM Counter-Earth: Is There Another Earth Hiding Behind The Sun? Can 2 Planets Shared an Orbit? https://youtu.be/rHITATBDvGs What's It Like Inside Jupiter? | What Scientists Discovered Within the Core of Jupiter Is Incredible https://youtu.be/H6XuC7tskxI NASA's ISSUES WARNING: Pluto Is Not What We Thought | Facts Nearly Everyone Gets Wrong About Pluto https://youtu.be/Ru6sz_gk4oM If you found this video informative, please give it a thumbs up, share it with your friends, and subscribe to our channel for more updates on space exploration and science news!
https://wn.com/Alfvén_Waves_The_Hidden_Force_Powering_Solar_Wind_|_New_Discovery_By_Esa_Nasa
Alfven wave
0:56

Alfven wave

  • Order:
  • Duration: 0:56
  • Uploaded Date: 01 Nov 2022
  • views: 623
I have been interested in a spectacular branch of physics, electric gas discharge, for a long time. In the tubes I have made, I observed this interesting, unconventional form of discharge in 1995. The regular spiral shape is formed in a very narrow parameter range. There are only guesses as why the plasma filament takes this regular form. In this video you can see one of my experiment with gas discharge. This tube has the following parameters.: Tube length: 800 mm Tube diameter: 26 mm Electrode distance: 720 mm Electrode: carbon Gas: air Tube pressure: 40 Torr Drive: HVDC #alfven #alfvenwave #mhd #plasmawave #plasma #gasdischarge
https://wn.com/Alfven_Wave
Alfvén wave Meaning
0:26

Alfvén wave Meaning

  • Order:
  • Duration: 0:26
  • Uploaded Date: 28 Apr 2015
  • views: 2250
Video shows what Alfvén wave means. A hydromagnetic shear wave in a charged plasma.. Alfvén wave Meaning. How to pronounce, definition audio dictionary. How to say Alfvén wave. Powered by MaryTTS, Wiktionary
https://wn.com/Alfvén_Wave_Meaning
Lecture 10 - Electromagnetic waves in a plasma, ordinary wave, extraordinary wave, cutoff, resonance
10:09

Lecture 10 - Electromagnetic waves in a plasma, ordinary wave, extraordinary wave, cutoff, resonance

  • Order:
  • Duration: 10:09
  • Uploaded Date: 18 May 2017
  • views: 26209
Electromagnetic waves in a plasma, ordinary wave, extraordinary wave, cutoff, resonance, Alfven wave. Lecturer: Joe Khachan from the School of Physics, The University of Sydney https://sydney.edu.au/science/schools/school-of-physics.html
https://wn.com/Lecture_10_Electromagnetic_Waves_In_A_Plasma,_Ordinary_Wave,_Extraordinary_Wave,_Cutoff,_Resonance
Kinetic Alfvén Waves
0:18

Kinetic Alfvén Waves

  • Order:
  • Duration: 0:18
  • Uploaded Date: 31 Mar 2017
  • views: 6322
In a kinetic Alfvén wave, some particles become trapped in the weak spots of the wave’s magnetic field and ride along with the wave as it moves through space. Credit: NASA Goddard's Scientific Visualization Studio/Tom Bridgman, data visualizer Related story: https://www.nasa.gov/feature/goddard/2017/nasa-observations-reshape-basic-plasma-wave-physics/
https://wn.com/Kinetic_Alfvén_Waves
mod11lec55 - Magnetohydrodynamics (MHD) : Waves in MHD - Alfven waves
29:37

mod11lec55 - Magnetohydrodynamics (MHD) : Waves in MHD - Alfven waves

  • Order:
  • Duration: 29:37
  • Uploaded Date: 08 Jun 2021
  • views: 6246
Derivation of the sound speed - recap, formal derivation of Alfven speed using perturbations in magnetized fluid
https://wn.com/Mod11Lec55_Magnetohydrodynamics_(Mhd)_Waves_In_Mhd_Alfven_Waves
Alfvén Wave
2:48

Alfvén Wave

  • Order:
  • Duration: 2:48
  • Uploaded Date: 04 Oct 2024
  • views: 0
Provided to YouTube by Routenote Alfvén Wave · sakanaxbt · sakana xbt Plasmaphysics ℗ sakanaxbt Released on: 2024-09-18 Auto-generated by YouTube.
https://wn.com/Alfvén_Wave
Alfven wave and equation for propagation of alfven wave #plasmaphysics #b.sc.part3physics
30:35

Alfven wave and equation for propagation of alfven wave #plasmaphysics #b.sc.part3physics

  • Order:
  • Duration: 30:35
  • Uploaded Date: 05 Feb 2023
  • views: 2167
#alfvenwave #equation for propagation of alfven wave and formula for alfven speed #v.v.i. #lecture5 #plasmaphysics #b.sc.part3physicshonours #m.sc.physics semester2 [correction : In the denominator of R.H.S. of equation 9, read or write z in place of t. Sorry for this inconvenience. Although equation 9 is not used further in this topic or video] Abhay Kumar Physics Quantum Classes
https://wn.com/Alfven_Wave_And_Equation_For_Propagation_Of_Alfven_Wave_Plasmaphysics_B.Sc.Part3Physics
PLAYLIST TIME:
  • Most Related
  • Most Recent
  • Most Popular
  • Top Rated
PLAYLIST TIME: 0:00 / 1:18:54

Typical Alfvén Waves

In a typical Alfvén wave, the particles (yellow) move freely along the magnetic field lines (blue). Credit: NASA Goddard's Scientific Visualization Studio/Tom Bridgman, data visualizer Related story: https://www.nasa.gov/feature/goddard/2017/nasa-observations-reshape-basic-plasma-wave-physics/
0:18
Typical Alfvén Waves
In a typical Alfvén wave, the particles (yellow) move freely along the magnetic field line...
published: 31 Mar 2017
Play in Full Screen
3:47
Alfvén Waves: The Hidden Force Powering Solar Wind | New Discovery by ESA & NASA
Alfvén Waves: The Hidden Force Powering Solar Wind | New Discovery by ESA & NASA Discover...
published: 29 Sep 2024
Play in Full Screen
0:56
Alfven wave
I have been interested in a spectacular branch of physics, electric gas discharge, for a l...
published: 01 Nov 2022
Play in Full Screen
0:26
Alfvén wave Meaning
Video shows what Alfvén wave means. A hydromagnetic shear wave in a charged plasma.. Alfv...
published: 28 Apr 2015
Play in Full Screen
10:09
Lecture 10 - Electromagnetic waves in a plasma, ordinary wave, extraordinary wave, cutoff, resonance
Electromagnetic waves in a plasma, ordinary wave, extraordinary wave, cutoff, resonance, A...
published: 18 May 2017
Play in Full Screen
0:18
Kinetic Alfvén Waves
In a kinetic Alfvén wave, some particles become trapped in the weak spots of the wave’s ma...
published: 31 Mar 2017
Play in Full Screen
29:37
mod11lec55 - Magnetohydrodynamics (MHD) : Waves in MHD - Alfven waves
Derivation of the sound speed - recap, formal derivation of Alfven speed using perturbatio...
published: 08 Jun 2021
Play in Full Screen
2:48
Alfvén Wave
Provided to YouTube by Routenote Alfvén Wave · sakanaxbt · sakana xbt Plasmaphysics ℗ s...
published: 04 Oct 2024
Play in Full Screen
30:35
Alfven wave and equation for propagation of alfven wave #plasmaphysics #b.sc.part3physics
#alfvenwave #equation for propagation of alfven wave and formula for alfven speed #v.v.i....
published: 05 Feb 2023
Play in Full Screen

Alfvén wave

In plasma physics, an Alfvén wave, named after Hannes Alfvén, is a type of magnetohydrodynamic wave in which ions oscillate in response to a restoring force provided by an effective tension on the magnetic field lines.

Definition

An Alfvén wave in a plasma is a low-frequency (compared to the ion cyclotron frequency) travelling oscillation of the ions and the magnetic field. The ion mass density provides the inertia and the magnetic field line tension provides the restoring force.

The wave propagates in the direction of the magnetic field, although waves exist at oblique incidence and smoothly change into the magnetosonic wave when the propagation is perpendicular to the magnetic field.

The motion of the ions and the perturbation of the magnetic field are in the same direction and transverse to the direction of propagation. The wave is dispersionless.

Alfvén velocity

The low-frequency relative permittivity \epsilon\, of a magnetized plasma is given by

where B\, is the magnetic field strength, c\, is the speed of light, \mu_0\, is the permeability of the vacuum, and \rho = \Sigma n_s m_s\, is the total mass density of the charged plasma particles. Here, s\, goes over all plasma species, both electrons and (few types of) ions.

'); } else { var query = elem.find('.keywords').html(); $.ajax({ context: elem, url: 'https://wn.com/api/upge/cheetah-search-adv/video', cache: true, data: { 'query': query }, dataType: 'jsonp', success: function(text) { if (text.length > 0) { video_id = text[0].id; elem.find('.player').html(''); } } }); } } var stopAllYouTubeVideos = function() { var iframes = document.querySelectorAll('iframe'); Array.prototype.forEach.call(iframes, function(iframe) { iframe.contentWindow.postMessage(JSON.stringify({ event: 'command', func: 'pauseVideo' }), '*'); }); } jQuery(function() { jQuery(".playVideo").live("click", function() { if(!$(this).hasClass("played")){ stopAllYouTubeVideos(); var elem = $(this); setTimeout(function(){ mouseOverMe(elem); }, 1000); } }); jQuery(".description_box .expandContent").live("click", function() { elem = $(this).parent().parent().parent().find('.descContent'); if(elem.height() > 51) { elem.css('height', '44px'); $(this).html('Show More '); }else{ elem.css('height', 'auto'); $(this).html('Hide '); } }); jQuery('.interview-play-off').click(function() { $(".interview-play-off").hide(); $(".interview-play").show(); $(".videoplayer-control-pause").click(); }); jQuery(".video-desc .show_author_videos").live("click", function() { query = $(this).attr('title'); container = $(this).parent().parent().parent().find('.video-author-thumbs'); $(this).parent().parent().parent().find('.video-author-thumbs').css('height', '220px'); jQuery.ajax({ url: '/api/upge/cheetah-photo-search/videoresults', data: {'query': query}, success: function(text) { if(!text) { text = i18n("No results"); } container.html(jQuery(text)); } }); }); }); // -->
×