IRIS Nugget
Welcome to the IRIS Science Nuggets: highlights of recent IRIS scientific results for the solar physics community.
{"id":"pod_polito_vanessa_2021-10-26T21:53:23.861Z","submitter":"Milan Gosic","author":"Milan Gosic [1,2], Bart De Pontieu [1,3,4], Luis R. Bellot Rubio [5], Alberto Sainz Dalda [1,2], Sara Esteban Pozuelo [5,6,7]","status":"published","creation-date":"2021-10-26T21:53:23.864Z","last-modified-date":"2021-11-10T20:10:04.704Z","credit":"[1] Lockheed Martin Solar and Astrophysics Laboratory, [2] Bay Area Environmental Research Institute, [3] Institute of Theoretical Astrophysics at the University of Oslo [4] Rosseland Centre for Solar Physics at the University of Oslo, [5] Instituto de Astrofisica de Andalucia, [6], Instituto de Astrofisica de Canarias, [7] Departamento de Astrofisica, Universidad de La Laguna","title":"Emergence of Internetwork Magnetic Fields through the Solar Atmosphere","contentBlocks":[{"type":"text","text":"Internetwork%20%28IN%29%20magnetic%20fields%20are%20weak%2C%20short-lived%2C%20but%20highly%20dynamic%20magnetic%20structures%20that%20emerge%20all%20over%20the%20Sun.%20They%20bring%20an%20enormous%20amount%20of%20magnetic%20flux%20to%20the%20solar%20surface%20and%20maintain%20the%20quiet%20Sun%20network%20%28NW%29.%20Because%20of%20this%2C%20IN%20fields%20are%20considered%20to%20be%20an%20essential%20contributor%20to%20the%20photospheric%20flux%20and%20energy%20budget%2C%20and%20may%20have%20a%20substantial%20impact%20on%20the%20energetics%20and%20dynamics%20of%20the%20upper%20solar%20atmosphere.%0A%0AThe%20presence%20of%20polarization%20signals%20due%20to%20IN%20magnetic%20fields%20in%20the%20chromosphere%20has%20not%20%20been%20observationally%20confirmed%20yet%20due%20to%20insufficient%20sensitivity%20of%20the%20available%20measurements.%20It%20is%20unknown%20if%20these%20fields%20can%20rise%20up%20to%20the%20chromosphere%20and%20beyond.%20Also%2C%20MHD%20models%20do%20not%20consistently%20show%20IN%20magnetic%20loops%20reaching%20the%20chromosphere.%20It%20is%20therefore%20necessary%20to%20study%20the%20possible%20presence%20and%20nature%20of%20IN%20fields%20in%20the%20upper%20atmosphere.%0A%0AIn%20this%20study%20we%20use%20coordinated%2C%20high-resolution%2C%20multi-wavelength%20observations%20obtained%20with%20the%20Interface%20Region%20Imaging%20Spectrograph%20%28IRIS%2C%20De%20Pontieu%20et%20al.%202014%29%20and%20the%20Swedish%201-m%20Solar%20Telescope%20%28SST%2C%20Scharmer%20et%20al.%202003%29%20to%20follow%20the%20evolution%20of%20IN%20magnetic%20loops%20emerging%20through%20the%20solar%20atmosphere.%20%0A%0AThe%20panels%20presented%20in%20Figure%201%20show%20three%20IN%20clusters%20%28the%20red%2C%20green%2C%20and%20blue%20contours%29%20emerging%20in%20the%20photosphere%20%28panels%20E%20and%20F%29%20and%20rinsing%20through%20the%20chromospheric%20layers%20%28G%29.%20%EF%BB%BFThe%20SJI%201400%20%26Aring%3B%20images%20%28H%29%20reveal%20a%20lot%20of%20bright%20loops%20connecting%20the%20footpoints%2C%20and%20also%20the%20footpoints%20with%20the%20surrounding%20NW%20patches.%20Many%20of%20these%20bright%20loops%20are%20the%20result%20of%20the%20heating%20generated%20by%20reconnection%20of%20the%20emerging%20and%20ambient%20magnetic%20field%20lines%20and%20are%20likely%20caused%20by%20Si%20IV%20emission.%20The%20C%20II%20and%20Si%20IV%20lines%20%28A%2C%20B%20and%20C%29%20indicate%20that%20the%20Doppler%20velocities%20change%20from%20blueshifts%20to%20redshifts%20when%20moving%20from%20the%20southern%20to%20the%20northern%20parts%20of%20the%20emission%20enhancement.%20This%20is%20compatible%20with%20what%20would%20be%20expected%20from%20bidirectional%20outflows%20produced%20by%20reconnection%20events%2C%20which%20lead%20to%20greatly%20broadened%20spectral%20lines."},{"type":"image","file":"","url":"nuggetvideos/2021/10/26/pod_polito_vanessa_2021-10-26T21%3A53%3A23.861Z/Fig1.png","hash":"6150e061434d99aeb879c46082642460","mimeType":"image/png","caption":"Figure%201%3A%20Upper%20row%3A%20IRIS%20rasters%20in%20the%20C%20II%201335%20%26Aring%3B%2C%20Si%20IV%201394%20%26Aring%3B%2C%20Si%20IV%201403%20%26Aring%3B%2C%20and%20Mg%20II%202796%20%26Aring%3B%20spectral%20domains.%20The%20black%2C%20red%2C%20and%20violet%20horizontal%20lines%20mark%20positions%20along%20the%20slit%20for%20which%20we%20analyzed%20in%20detail%20the%20recorded%20IRIS%20FUV%20and%20NUV%20spectra.%20Bottom%20row%3A%20SST%20continuum%20intensity%20maps%20and%20magnetograms%20in%20the%20Fe%20I%206173%20%26Aring%3B%20line%2C%20IRIS%20SJI%202796%20%26Aring%3B%20and%20SJI%201400%20%26Aring%3B%20intensity%20maps."},{"type":"text","text":"The%20chromospheric%20response%20to%20the%20emerging%20IN%20fields%20can%20be%20seen%20in%20the%20Ca%20II%20and%20H%CE%B1%20images.%20They%20show%20us%20that%20the%20chromospheric%20fibrils%20have%20completely%20changed%20their%20morphology%20during%20the%20emergence%20of%20the%20three%20IN%20clusters.%20Figure%202%20%28panels%20A%20to%20D%29%20shows%20one%20of%20the%20most%20interesting%20moments%20when%20long%20and%20wide%20blueshifted%20H%CE%B1%20absorption%20features%20appear%20above%20the%20negative-polarity%20footpoints%2C%20and%20extend%20down%20to%20the%20positive-polarity%20NW%20patch.%20They%20may%20outline%20magnetic%20field%20lines%20rising%20intermittently%20through%20the%20atmosphere%20and%20reconnecting%20with%20the%20ambient%20fields%20above.%20Simultaneously%2C%20the%20Ca%20II%20images%20%28E%20to%20G%29%20reveal%20the%20fibrils%20clearly%20rooted%20in%20the%20footpoints%20of%20the%20clusters.%20After%20the%20blueshift%20event%2C%20the%20Ca%20II%20magnetograms%20%28H%29%20start%20showing%20the%20positive-%20and%20negative-polarity%20footpoints%20created%20by%20the%20three%20clusters."},{"type":"image","file":"","url":"nuggetvideos/2021/10/26/pod_polito_vanessa_2021-10-26T21%3A53%3A23.861Z/Fig2.png","hash":"46655d4743c8f81f6629550531af6bfa","mimeType":"image/png","caption":"Figure%202%3A%20Chromospheric%20fibrils%20above%20the%20emerging%20IN%20flux%20region%20can%20be%20seen%20as%20blueshifted%20H%CE%B1%20absorption%20features%20%28panels%20A%20to%20D%29%20and%20in%20the%20Ca%20II%20filtergrams%20at%20%E2%88%920.2%20%26Aring%3B%20%28panel%20E%29%2C%20the%20line%20core%20%28F%29%2C%20and%200.2%20%26Aring%3B%20%28G%29.%20The%20panel%20%28H%29%20displays%20the%20Ca%20II%20magnetogram%20showing%20the%20negative-polarity%20IN%20footpoints%20appearing%20in%20the%20chromosphere%20%28green%20contour%29."},{"type":"text","text":"The%20scenario%20in%20which%20the%20newly%20emerging%20fields%20rise%20through%20the%20solar%20atmosphere%20and%20interact%20with%20the%20ambient%20fields%20is%20supported%20by%20the%20FUV%20IRIS%20spectra.%20Figure%203%20shows%20several%20UV%20spectral%20profiles%20at%20different%20locations%20along%20the%20slit.%20They%20exhibit%20enhanced%20emission%20with%20broad%20wings%2C%20and%20are%20non-Gaussian%2C%20mostly%20triangular-shaped%20profiles%2C%20similar%20to%20previous%20observations%20of%20plasmoid-mediated%20magnetic%20reconnection%20%28Innes%20et%20al.%201997%2C%202015%3B%20Rouppe%20van%20der%20Voort%20et%20al.%202017%29."},{"type":"image","file":"","url":"nuggetvideos/2021/10/26/pod_polito_vanessa_2021-10-26T21%3A53%3A23.861Z/Fig3.png","hash":"89c8377dc78bf0da76292faad4554775","mimeType":"image/png","caption":"Figure%203%3A%20Selected%20spectral%20profiles%20in%20the%20IRIS%20C%20II%201335%20%26Aring%3B%20%28upper%20left%29%2C%20Si%20IV%201394%20%26Aring%3B%20%28upper%20right%29%2C%20Si%20IV%201403%20%26Aring%3B%20%28lower%20left%29%2C%20and%20Mg%20II%20h%20and%20k%20lines%20at%20different%20locations%20along%20the%20slit."},{"type":"text","text":"From%20%5Cbegin%7Bequation%7DIRIS%5E2%5Cend%7Bequation%7D%20inversions%20of%20the%20observed%20IRIS%20Mg%20II%20spectral%20profiles%20we%20estimated%20that%20the%20highest%20temperatures%20are%20at%20the%20locations%20of%20NW%20magnetic%20elements%20and%20above%20the%20emerging%20flux%20region.%20This%20can%20be%20seen%20in%20the%20left%20panel%20of%20Figure%204.%20The%20temperature%20is%20higher%20along%20the%20loops%2C%20compared%20to%20the%20non-emerging%20quiet%20Sun%20flux%20regions.%20LOS%20plasma%20velocities%20within%20the%20emerging%20region%20are%20shown%20in%20the%20right%20panel%20and%20reveal%20that%20there%20are%20strong%20chromospheric%20upflows%20close%20to%20the%20loop%20tops%20%28about%20%E2%88%925%20km%2Fs%29%2C%20and%20downflows%20%28%E2%88%BC10%20km%2Fs%29%20at%20the%20positions%20of%20the%20footpoints.%20These%20results%20further%20establish%20our%20picture%20of%20plasma%20being%20pushed%20up%20to%20the%20chromosphere%20with%20plasma%20draining%20from%20the%20loops%20in%20the%20more%20vertically%20oriented%20footpoints."},{"type":"image","file":"","url":"nuggetvideos/2021/10/26/pod_polito_vanessa_2021-10-26T21%3A53%3A23.861Z/Fig4.png","hash":"1a9b83a32595c42d370b6b700f365b5f","mimeType":"image/png","caption":"Figure%204%3A%20%5Cbegin%7Bequation%7DIRIS%5E2%5Cend%7Bequation%7D%20inversions%20showing%20the%20temperature%20%28left%29%20and%20LOS%20velocity%20%28right%29%20maps%20at%20%5Cbegin%7Bequation%7Dlog_%7B10%7D%5Ctau_%7B500%7D%3D-5.8%5Cend%7Bequation%7D.%20The%20temperature%20map%20shows%20higher%20values%20within%20the%20flux%20emerging%20region.%20The%20LOS%20velocities%20reveal%20upflows%20around%20the%20loop%20tops%20and%20downflows%20that%20coincide%20with%20the%20footpoints%20and%20NW%20elements."},{"type":"text","text":"Our%20polarimetric%20observations%20obtained%20with%20SST%20in%20the%20Fe%20I%206173%20%26Aring%3B%2C%20Mg%20I%20b2%205173%20%26Aring%3B%20and%20Ca%20II%208542%20%26Aring%3B%20lines%20show%20three%20IN%20bipoles%20as%20they%20appear%20in%20the%20photosphere%20and%20rise%20up%20through%20the%20solar%20atmosphere.%20They%20provide%20the%20first%20direct%20observational%20evidence%20that%20IN%20fields%20are%20capable%20of%20reaching%20the%20chromosphere%2C%20and%20locally%20heating%20the%20upper%20solar%20atmosphere.%20According%20to%20our%20observations%2C%20it%20took%20about%20one%20hour%20for%20the%20IN%20fields%20to%20break%20through%20the%20ambient%20fields%20and%20emerge%20in%20the%20chromosphere.%20We%20estimated%20from%20the%20IRIS%20inversions%20of%20the%20Mg%20II%20h%20and%20k%20lines%20that%20the%20chromospheric%20temperature%20above%20the%20emerging%20IN%20fields%20rises%20up%20to%2010%20kK%20%28from%205-6%20kK%20in%20the%20very%20quiet%20regions%29."}],"references":["<a href=\"https://ui.adsabs.harvard.edu/abs/2014SoPh..289.2733D/abstract\">De Pontieu, B., Title, A. M., Lemen, J. R., et al. 2014, SoPh, 289, 2733</a>","<a href=\"https://ui.adsabs.harvard.edu/abs/2021ApJ...911...41G/abstract\">Gosic, M., De Pontieu, B., Bellot Rubio, L. R., et al. 2021, ApJ, 911, 41</a>","<a href=\"https://ui.adsabs.harvard.edu/abs/2015ApJ...813...86I/abstract\">Innes, D. E., Guo, L.-J., Huang, Y.-M., & Bhattacharjee, A. 2015, ApJ, 813, 86</a>","<a href=\"https://ui.adsabs.harvard.edu/abs/1997Natur.386..811I/abstract\">Innes, D. E., Inhester, B., Axford, W. I., & Wilhelm, K. 1997, Natur, 386, 811</a>","<a href=\"https://ui.adsabs.harvard.edu/abs/2014Sci...346C.315P/abstract\">Peter, H., Tian, H., Curdt, W., et al. 2014, Sci, 346, 1255726</a>","<a href=\"https://ui.adsabs.harvard.edu/abs/2017ApJ...851L...6R/abstract\">Rouppe van der Voort, L., De Pontieu, B., Scharmer, G. B., et al. 2017, ApJL, 851, L6</a>","<a href=\"https://ui.adsabs.harvard.edu/abs/2019ApJ...875L..18S/abstract\">Sainz Dalda, A., de la Cruz Rodriguez, J., De Pontieu, B., & Gosic, M. 2019, ApJL, 875, L18</a>","<a href=\"https://ui.adsabs.harvard.edu/abs/2003SPIE.4853..341S/abstract\">Scharmer, G. B., Bjelksjo, K., Korhonen, T. K., Lindberg, B., & Petterson, B. 2003a, in Innovative Telescopes and Instrumentation for Solar Astrophysics, eds. S. L. Keil, & S. V. Avakyan, Proc. SPIE, 4853, 341</a>","",""],"pubDate":"2021-11-10T20:10:09.592Z"}