Secondary ribbons found in the flare Hα filtergrams Pavel Kotrč and Miroslav Bárta, Astronomical institute AS ČR, Ondřejov Václav Šebelík, University of South Bohemia, České Budějovice Jiří Žák, Gymnázium Jarošova, Brno Wolfgang Poetzi, Kanzelhohe Solar Observatory, Austria Abstract. Recent models of solar flares deal with high resolution MHD simulations. Energy transfer from large to small scales can be explained by a cascade reconnection model (Bárta et al, 2011a). The model also describes an origin and movement of plasmoids during flare development and predicts a specific structures and behavior of flare kernels that can become evident in the observation. It concerns particularly the secondary ribbons occurring temporarily in solar flares. A first indication of such observation was published recently (Bárta et al, 2011b). Here we report on results of a more extensive analysis of H-alpha filtegrams of solar flares. We studied H-alpha filtergrams of the Kanzelhohe Solar Observatory for the most energetic solar flares in the period 1973 till 2014. We analyzed flare images in all flare phases with emphasize on the intensity profile put perpendicularly to the axes of ribbons. We report on several cases of possible secondary flare ribbons and on the study of their kinematic parameters. Bairisch Koeldorf, Workshop April 2014 1
Solar flare models A standard scenario reconnection A good agreement of models and observations for large scales Flare model scheme: http://solarmuri.ssl.berkeley.edu/~hhudson/cartoons/ (K. Shibata, P. Gallagher) Bairisch Koeldorf, Workshop April 2014 2
Solar flare mechanism magnetic field reconnection X point & current sheet Bairisch Koeldorf, Workshop April 2014 3
Numerical modelling of reconnection: Bairisch Koeldorf, Workshop April 2014 4
Flare modelling: Reconection of magnetic field Shibata, K. & Tanuma, S. 2001, Bairisch Koeldorf, Workshop April 2014 5
Spontaneous Current-layer Fragmentation and Cascading Reconnection in Solar Flares. I. Model and Analysis Bárta et al., ApJ (2011a), Bairisch Koeldorf, Workshop April 2014 6
Bárta et al., ApJ (2011b), Bairisch Koeldorf, Workshop April 2014 7
A solar flare See the absorption features in Ha) Bairisch Koeldorf, Workshop April 2014 8
Numerical modelling of flares: Relation to observation Structuring of chromospheric flare ribbons Bairisch Koeldorf, Workshop April 2014 9
Numerical modelling of flares: Relation to observation Structuring of chromospheric flare ribbons Plasmoid? Ondrejov MCF Spectrograph, Kotrč, 2009 Bairisch Koeldorf, Workshop April 2014 10
Diagnostics in optical region four-ribbon flare: A rare and specific effect predicted by a reconnection model based on plasmoids Bairisch Koeldorf, Workshop April 2014 11
A search in existing archives (Ondrejov, Catania, Hvar NO) List of observed flares 1 B + (source digitized films & CCD) Since 1988 till 2013, full disk H-alpha images with flares Films data converted from densities to relative intensities A simple code for photometric scans across the ribbons 19.10.1989 12:30:00 12:54:00 15:52:00 D S24 E07 4B 6.3.1989 13:57:00 14:11:00 16:14:00 D N32 E67 3B 5.5.1989 7:24:00 7:40:00 11:05:00 D N29 E06 3B 30.6.1988 9:05:00 9:05:00 9:37:00 S16 E22 2B 3.10.1988 14:49:00 15:10:00 15:35:00 D S27 W17 2B 10.3.1989 10:42:00 11:34:00 12:12:00 D N35 E27 2B 12.8.1989 14:53:00 E 0:00:00 16:44:00 D S15 W41 2B 23.10.1989 12:36:00 12:44:00 13:44:00 S28 W41 2B 2.11.1989 12:19:00 12:51:00 13:25:00 N19 E73 2B 21.4.1984 14:23:00 14:58:00 15:28:00 S08 E69 1B 26.4.1984 8:56:00 9:00:00 9:24:00 S07 E32 1B 26.4.1984 12:46:00 12:50:00 13:11:00 D S11 E16 1B 27.4.1984 13:53:00 14:11:00 16:03:00 D S08 E07 1B 24.7.1987 9:58:00 10:05:00 10:57:00 S27 W36 1B 19.8.1988 13:40:00 13:44:00 14:06:00 N25 W77 1B 29.12.1988 11:54:00 11:58:00 13:58:00 D S22 W15 1B 7.3.1989 13:20:00 13:24:00 13:47:00 N29 E66 1B 30.7.1990 6:32:00 7:31:00 8:10:00 D N18 E44 3B 27.2.1992 9:23:00 9:57:00 U 13:59:00 N07 W02 3B 2.5.1998 13:35:00 E 13:47:00 14:45:00 D S15 W14 3B 23.9.1998 6:44:00 7:02:00 7:57:00 D N18 E10 3B 2.7.1993 13:19:00 E 13:19:00 U 14:00:00 S11 W13 3B 10.11.1990 11:56:00 12:00:00 12:41:00 N06 E17 2B 23.12.1990 9:43:00 10:01:00 10:27:00 N12 W73 2B 30.1.1991 8:50:00 9:02:00 10:18:00 S09 W35 2B 14.2.1991 12:31:00 12:35:00 13:14:00 N10 W48 2B 5.7.1991 8:38:00 E 8:46:00 9:01:00 D N26 E28 2B 6.2.1992 9:35:00 10:20:00 13:21:00 D S15 W07 2B 14.2.1993 12:47:00 12:55:00 13:23:00 S21 E74 2B 27.11.1997 13:01:00 13:17:00 13:37:00 N15 E63 2B 23.5.1990 7:31:00 8:18:00 8:44:00 D S15 W60 1B 16.3.1991 10:49:00 10:53:00 11:28:00 S11 E05 1B 21.3.1991 10:29:00 10:33:00 10:48:00 S23 E48 1B 19.5.1991 13:43:00 13:55:00 15:11:00 S12 E16 1B 28.5.1991 15:02:00 15:18:00 15:40:00 D N08 E57 1B 28.5.1991 16:14:00 16:26:00 16:44:00 N07 E54 1B 24.4.1992 12:45:00 12:53:00 13:49:00 N10 E04 1B 20.8.1992 8:54:00 9:10:00 9:56:00 N15 W25 1B 1.4.1997 13:43:00 E 13:50:00 U 13:50:00 D S25 E16 1B 28.10.2003 10:32:00 E 11:23:00 U 14:20:00 S16 E07 4B 26.10.2003 6:46:00 E 6:46:00 E 9:17:00 S14 E41 3B 16.7.2004 13:50:00 13:57:00 14:31:00 D S09 E29 3B 20.7.2004 12:26:00 12:31:00 13:30:00 N10 E32 3B 17.1.2005 7:16:00 E 9:51:00 11:57:00 N14 W24 3B 12.7.2000 10:26:00 E 10:36:00 10:40:00 D N17 E25 2B 20.11.2003 7:35:00 7:42:00 8:43:00 N01 W08 2B 12.5.2005 7:28:00 7:34:00 8:57:00 N12 E28 2B 30.7.2005 6:28:00 E 6:30:00 U 8:05:00 N11 E57 2B 19.10.2001 9:21:00 9:43:00 10:17:00 S17 W47 1B 11.4.2013 6:56:00 7:08:00 9:15:00 N08 E14 3B 4.7.2012 7:19:00 E 7:19:00 E 9:25:00 S18 W17 2B 3.8.2011 13:16:00 13:52:00 13:56:00 D N17 W28 2B 9.8.2011 7:54:00 8:14:00 U 9:03:00 U N17 W69 2B 15.10.2013 8:23:00 U 8:39:00 9:52:00 S21 W13 1B 16.10.2013 14:26:00 14:32:00 14:52:00 S21 W30 1B 26.10.2013 8:26:00 8:55:00 9:20:00 S11 W23 1B 26.10.2013 9:18:00 9:21:00 10:26:00 S09 E54 1B Selection of a sub image, making a photometric profile In positive cases fitting by 4 gaussians deriving the positions of ribbons 26.10.2013 9:23:00 9:25:00 9:43:00 N07 W49 1B 23.12.2013 9:03:00 9:06:00 9:12:00 S17 W62 1B 9.5.2012 14:22:00 E 14:22:00 E 14:25:00 D N13 E30 1B 28.6.2012 16:09:00 U 16:12:00 16:21:00 U N16 E47 1B 29.6.2012 9:14:00 9:21:00 9:31:00 N16 E37 1B 4.7.2012 9:41:00 9:55:00 10:56:00 S18 W17 1B 5.7.2012 11:38:00 11:44:00 12:10:00 S18 W33 1B Bairisch Koeldorf, Workshop April 2014 12
Flare on 05th May 1989, 3B, N29, E06, 7:24-11;05 UT, 07:32:04 UT Bairisch Koeldorf, Workshop April 2014 13
Flare on 20th April 1990, 3N, N10, W48, 08:30-09:51 UT, 08:38:14 UT Bairisch Koeldorf, Workshop April 2014 14
Flare on 15th May 1990, 3N, N38, E36, 14:11-15:29 UT, 14:13:00 UT Bairisch Koeldorf, Workshop April 2014 15
Flare on 15th May 1990, 3N, N38, E36, 14:11-15:29 UT, 14:49:04 UT Bairisch Koeldorf, Workshop April 2014 16
Discussion Recent models of reconnection in flares expect that plasmoids play a significant role. One of the key prediction of the model is a possibility of temporal existence of the multifold flare ribbons during the interaction of the plasmoid with the flare-loop arcade. Thus, finding the multiple pairs of the flare ribbons would represent a significant evidence in favor of the plasmoid-dominated magnetic reconnection in solar flares. For search of 4-ribbon flares we found no ribbon flare catalogue. Existing archives do not provide information about two ribbon flares. Thus the search for flares was more difficult than we expected. Bairisch Koeldorf, Workshop April 2014 17
Summary 3 examples of the model-predicted phenomena were probably found Flare secondary ribbons can be well separated from the main ones Studied phenomena occurred in all phases of flares on solar disk Study of fine structures in flare ribbons (H-alpha emission/absorption) is important for specification structures in chromosphere and lower corona and for testing of existing flare models Further observation with a better spatial resolution is highly recommended UV, EUV and Radio data provide more complementary infomation Bairisch Koeldorf, Workshop April 2014 18
Thank you for attention The research leading to these results has received funding from the European Community s Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 606862 (F-CHROMA). Bairisch Koeldorf, Workshop April 2014 19