{"id":11825,"date":"2017-03-26T07:32:50","date_gmt":"2017-03-26T07:32:50","guid":{"rendered":"http:\/\/revoscience.com\/en\/?p=11825"},"modified":"2017-03-26T07:32:50","modified_gmt":"2017-03-26T07:32:50","slug":"supersonic-plasma-jets-discovered","status":"publish","type":"post","link":"https:\/\/www.revoscience.com\/en\/supersonic-plasma-jets-discovered\/","title":{"rendered":"Supersonic plasma jets discovered"},"content":{"rendered":"
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Birkeland currents<\/figcaption><\/figure>\n

Information from ESA\u2019s magnetic field Swarm mission has led to the discovery of supersonic plasma jets high up in our atmosphere that can push temperatures up to almost 10 000\u00b0C.<\/span><\/p>\n

Presenting these findings at this week\u2019s Swarm Science Meeting in Canada, scientists from the University of Calgary explained how they used measurements from the trio of Swarm satellites to build on what was known about vast sheets of electric current in the upper atmosphere.<\/span><\/p>\n

The theory that there are huge electric currents, powered by solar wind and guided through the ionosphere by Earth\u2019s magnetic field, was postulated more than a century ago by Norwegian scientist Kristian Birkeland.<\/span><\/p>\n

It wasn\u2019t until the 1970s, after the advent of satellites, however, that these \u2018Birkeland currents\u2019 were confirmed by direct measurements in space.<\/span><\/p>\n

These currents carry up to 1 TW of electric power to the upper atmosphere \u2013 about 30 times the energy consumed in New York during a heatwave.<\/span><\/p>\n

They are also responsible for \u2018aurora arcs\u2019, the familiar, slow-moving green curtains of light that can extend from horizon to horizon.<\/span><\/p>\n

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Magnetic field sources<\/figcaption><\/figure>\n

While much is known about these current systems, recent observations by Swarm have revealed that they are associated with large electrical fields.<\/span><\/p>\n

These fields, which are strongest in the winter, occur where upwards and downwards Birkeland currents connect through the ionosphere.<\/span><\/p>\n

Bill Archer from the University of Calgary explained, \u201cUsing data from the Swarm satellites\u2019 electric field instruments, we discovered that these strong electric fields drive supersonic plasma jets.<\/span><\/p>\n

\u201cThe jets, which we call \u2018Birkeland current boundary flows\u2019, mark distinctly the boundary between current sheets moving in opposite direction and lead to extreme conditions in the upper atmosphere.<\/span><\/p>\n

\u201cThey can drive the ionosphere to temperatures approaching 10 000\u00b0C and change its chemical composition. They also cause the ionosphere to flow upwards to higher altitudes where additional energisation can lead to loss of atmospheric material to space.\u201d<\/span><\/p>\n

David Knudsen, also from the University of Calgary, added, \u201cThese recent findings from Swarm add knowledge of electric potential, and therefore voltage, to our understanding of the Birkeland current circuit, perhaps the most widely recognised organising feature of the coupled magnetosphere\u2013ionosphere system.\u201d<\/span><\/p>\n

This discovery is just one of the new findings presented at the week-long science meeting dedicated to the Swarm mission. Also presented this week and focusing on Birkeland currents, for example, Swarm was used to confirm that these currents are stronger in the northern hemisphere and vary with the season.<\/span><\/p>\n

Since they were launched in 2013, the identical Swarm satellites have been measuring and untangling the different magnetic signals that stem from Earth\u2019s core, mantle, crust, oceans, ionosphere and magnetosphere.<\/span><\/p>\n

As well as a package of instruments to do this, each satellite has an electric field instrument positioned at the front to measure plasma density, drift and velocity.Rune Floberghagen, ESA\u2019s Swarm mission manager, said, \u201cThe electric field instrument is the first ionospheric imager in orbit so it\u2019s very exciting to see such fantastic results that are thanks to this new instrument.\u201cThe dedication of scientists working with data from the mission never ceases to amaze me and we are seeing some brilliant results, such as this, discussed at this week\u2019s meeting.\u201cSwarm is really opening our eyes to the workings of the planet from deep down in Earth\u2019s core to the highest part of our atmosphere.\u201d<\/span><\/div>\n","protected":false},"excerpt":{"rendered":"

Information from ESA\u2019s magnetic field Swarm mission has led to the discovery of supersonic plasma jets high up in our atmosphere that can push temperatures up to almost 10 000\u00b0C. Presenting these findings at this week\u2019s Swarm Science Meeting in Canada, scientists from the University of Calgary explained how they used measurements from the trio […]<\/p>\n","protected":false},"author":6,"featured_media":11826,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[20],"tags":[],"class_list":["post-11825","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-space-news"],"featured_image_urls":{"full":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Birkeland_currents_node_full_image_2.jpg",495,700,false],"thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Birkeland_currents_node_full_image_2-150x150.jpg",150,150,true],"medium":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Birkeland_currents_node_full_image_2-212x300.jpg",212,300,true],"medium_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Birkeland_currents_node_full_image_2.jpg",495,700,false],"large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Birkeland_currents_node_full_image_2.jpg",495,700,false],"1536x1536":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Birkeland_currents_node_full_image_2.jpg",495,700,false],"2048x2048":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Birkeland_currents_node_full_image_2.jpg",495,700,false],"ultp_layout_landscape_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Birkeland_currents_node_full_image_2.jpg",495,700,false],"ultp_layout_landscape":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Birkeland_currents_node_full_image_2.jpg",403,570,false],"ultp_layout_portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Birkeland_currents_node_full_image_2.jpg",495,700,false],"ultp_layout_square":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Birkeland_currents_node_full_image_2.jpg",424,600,false],"newspaper-x-single-post":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Birkeland_currents_node_full_image_2.jpg",347,490,false],"newspaper-x-recent-post-big":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Birkeland_currents_node_full_image_2.jpg",255,360,false],"newspaper-x-recent-post-list-image":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Birkeland_currents_node_full_image_2.jpg",46,65,false],"web-stories-poster-portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Birkeland_currents_node_full_image_2.jpg",495,700,false],"web-stories-publisher-logo":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Birkeland_currents_node_full_image_2.jpg",68,96,false],"web-stories-thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Birkeland_currents_node_full_image_2.jpg",150,212,false]},"author_info":{"info":["Amrita Tuladhar"]},"category_info":"Space\/ AstroPhysics<\/a>","tag_info":"Space\/ AstroPhysics","comment_count":"0","_links":{"self":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/11825","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/comments?post=11825"}],"version-history":[{"count":0,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/11825\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media\/11826"}],"wp:attachment":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media?parent=11825"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/categories?post=11825"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/tags?post=11825"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}