{"id":"pod_polito_vanessa_2022-05-26T17:47:04.706Z","submitter":"Andrew Hillier","author":"Andrew Hillier[1] & Vanessa Polito[2,3]","status":"published","creation-date":"2022-05-26T17:47:04.736Z","last-modified-date":"2022-06-14T17:04:29.93Z","credit":"[1] CEMPS, University of Exeter, Exeter EX4 4QF U.K, [2] Bay Area Environmental Research Institute, NASA Research Park, Moffett Field, CA 94035, USA, [3] Lockheed Martin Solar & Astrophysics Laboratory, Org. A021S, Bldg. 252, 3251 Hanover St., Palo Alto, CA 94304, USA","title":"IRIS observations of bi-directional jets in a prominence as signatures of magnetic reconnection","contentBlocks":[{"type":"text","text":"Space-based%20observations%20of%20quiescent%20prominences%20in%20cool%20spectral%20lines%2C%20including%20those%20by%20IRIS%2C%20show%20that%20many%20of%20these%20prominences%20are%20highly%20dynamic%2C%20with%20observations%20showing%20transonic%20downflows%20%28Chae%202010%29%20and%20instabilities%20%28Berger%20et%20al%202010%29.%20There%20are%20a%20number%20of%20instances%20where%20magnetic%20reconnection%20of%20the%20prominence%20magnetic%20field%20has%20been%20invoked%20to%20explain%20how%20flows%20are%20being%20driven%20%28e.g.%20Chae%202010%2C%20Hillier%20et%20al%202011%29.%20However%2C%20clear%20evidence%20that%20the%20internal%20magnetic%20fields%20of%20a%20prominence%20can%20become%20sufficiently%20stressed%20to%20then%20reconnect%20and%20drive%20flows%20has%20proved%20elusive.%20It%20is%20exactly%20this%20evidence%20that%20has%20been%20found%20in%20IRIS%20prominence%20observations."},{"type":"image","file":"","url":"nuggetvideos/2022/05/26/pod_polito_vanessa_2022-05-26T17%3A47%3A04.706Z/Figure1a.png","hash":"aa79b92f4ad62b247e40745bb4e6e3f8","mimeType":"image/png","caption":"Figure%201.%20Quiescent%20prominence%20observed%20by%20IRIS%20on%20the%20South-East%20limb%20of%20the%20Sun%20in%20the%20Mg%20II%20k%20line.%20Region%20shown%20in%20the%20left%20panel%20of%20Figure%202%20highlighted%20by%20the%20yellow%20box."},{"type":"text","text":"A%20quiescent%20prominence%20%28shown%20in%20Figure%201%29%20was%20observed%20with%20IRIS%20on%20the%20South-East%20limb%20of%20the%20Sun%20on%20June%2030%2C%202015%20between%206%3A57%20UT%20and%2011%3A20%20UT.%20This%20prominence%20presented%20many%20interesting%20dynamic%20features%20including%20multiple%20downflows%20and%20upflows%20%28e.g.%20see%20Hillier%20%26amp%3B%20Polito%202018%29.%20In%20these%20observations%20one%20particular%20interesting%20phenomenon%20could%20be%20observed%3A%20the%20formation%20of%20bi-directional%20jets%20of%20prominence%20material%20%28Hillier%20%26amp%3B%20Polito%202021%29."},{"type":"image","file":"","url":"nuggetvideos/2022/05/26/pod_polito_vanessa_2022-05-26T17%3A47%3A04.706Z/Figure2_nugget.jpg","hash":"8b81085e70df4a362a5681a5c81f1411","mimeType":"image/jpeg","caption":"Figure%202.%20Body%20of%20the%20prominence%20as%20observed%20in%20MgII%20k%20%28left-hand%20panels%29.%20The%20right-hand%20panels%20show%20the%20temporal%20evolution%20in%20the%20white%20box%20in%20the%20left%20panel.%20Motion%20of%20blobs%20along%20the%20plasma%20sheet%20is%20tracked%20by%20the%20arrows."},{"type":"text","text":"What%20separates%20these%20jets%20from%20all%20the%20other%20prominence%20flows%20that%20have%20been%20previously%20reported%20is%20that%20they%20are%20bi-directional.%20By%20this%20we%20mean%20that%20from%20a%20single%20local%20point%2C%20material%20is%20observed%20to%20be%20ejected%20at%20speeds%20up%20to%2010%20km%2Fs%20in%20two%20opposite%20directions.%20These%20ejections%20formed%20in%20regions%20where%20long%20plasma%20sheets%20developed%2C%20and%20were%20composed%20of%20multiple%20plasma%20blobs.%20We%20observe%20flows%20bringing%20material%20into%20some%20of%20these%20jets%20as%20well%20as%20the%20outward%20ejections%2C%20and%20even%20in%20one%20case%20the%20late%20evolution%20of%20the%20jet%20appears%20to%20show%20the%20presence%20of%20flow-driven%20instabilities%20similar%20to%20those%20observed%20by%20Hillier%20%26amp%3B%20Polito%202018.%20The%20observations%20here%20present%20all%20the%20hall-marks%20of%20jets%20driven%20by%20magnetic%20reconnection%2C%20i.e.%20a%20current%20sheet%20%28the%20observed%20plasma%20sheet%29%20developing%20magnetic%20reconnection%20producing%20reconnection%20jets%20%28the%20observed%20bi-directional%20jets%29.%20%0A%0AUnderstanding%20that%20these%20jets%20can%20be%20created%20by%20magnetic%20reconnection%20means%20we%20can%20learn%20something%20about%20the%20prominence%20environment.%20For%20example%20the%20intensity%20of%20the%20current%20sheet%20suggests%20a%20prominence%20magnetic%20field%20of%204.5%20G%20to%209.2%20G%20with%20the%20reconnected%20component%20of%20the%20magnetic%20field%20around%201%20G%20needed%20to%20explain%20the%20speed%20of%20the%20ejections.%20Some%20open%20questions%20remain%20though.%20Are%20the%20blobs%20that%20are%20being%20emitted%20plasmoids%20creating%20by%20tearing%20of%20the%20current%20sheet%3F%20If%20they%20are%20then%20the%20size%20of%20the%20blobs%20doesn%E2%80%99t%20scale%20as%20expected%20with%20the%20observed%20thickness%20of%20the%20current%20sheet.%20If%20these%20are%20not%20plasmoids%20created%20by%20current-sheet%20tearing%20then%20it%20opens%20up%20other%20possibilities%2C%20for%20example%20that%20they%20are%20observations%20of%20slow-mode%20shocks%20created%20by%20the%20reconnection.%20%0A%0AIn%20this%20article%20we%20have%20presented%20evidence%2C%20in%20the%20form%20of%20observations%20of%20bursty%20bi-directional%20jet%20formation%2C%20that%20reconnection%20of%20the%20internal%20magnetic%20field%20of%20a%20quiescent%20prominence%20can%20occur.%20With%20so%20many%20fantastic%20observations%20of%20prominences%20in%20the%20IRIS%20archive%20it%20is%20likely%20that%20many%20more%20of%20these%20events%20can%20be%20found."}],"references":["<a href=\"https://ui.adsabs.harvard.edu/abs/2010ApJ...716.1288B/abstract\">Berger, T. E., Slater, G., Hurlburt, N., et al. 2010, ApJ, 716, 1288</a>","<a href=\"https://ui.adsabs.harvard.edu/abs/2010ApJ...714..618C/abstract\">Chae, J. 2010, ApJ, 714, 618</a>","<a href=\"https://ui.adsabs.harvard.edu/abs/2011PASJ...63L..19H/abstract\">Hillier, A., Isobe, H., & Watanabe, H. 2011, PASJ, 63, 19</a>","<a href=\"https://ui.adsabs.harvard.edu/abs/2018ApJ...864L..10H/abstract\">Hillier, A., & Polito, V. 2018, ApJ, 864, L10</a>","<a href=\"https://ui.adsabs.harvard.edu/abs/2021A%26A...651A..60H/abstract\">Hillier, A., & Polito, V. 2021, A&A, 651, A60</a>","","","","",""],"pubDate":"2022-06-14T17:04:53.571Z"}