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Solar Activity Affecting Space Weather

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Solar Activity Affecting Space Weather March 7, 2006, STP11, Rio de Janeiro, Brazil Solar Activity Affecting Space Weather Kazunari Shibata Kwasan and Hida Observatories Kyoto University, Japan contents • Introduction • Flares • Coronal Mass Ejections（CME) • Solar Wind • Future Projects Japanese newspaper reporting the big flare of Oct 28, 2003 and its impact on the Earth big flare (third largest flare in record) on Oct 28, 2003 X17 X-ray Intensity time A big flare on Oct 28, 2003 （third largest X-ray intensity in record） EUV Visible light ＳＯＨＯ／ＥＩＴ ＳＯＨＯ／ＬＡＳＣＯ • Flare occurred at UT11:00 on Oct 28 Magnetic Storm on the Earth Around UT 6:00- Aurora observed in Japan on Oct 29, 2003 at around UT 14:00 on Oct 29, 2003 During CAWSES campaign observations (Shinohara) Xray X17 X6.2 Proton 10MeV 100MeV Vsw 44h 30h Bt Bz Dst Flares What is a flare ? Ｈα chromosphere 10,000 K Discovered in Mid 19C Near sunspots＝＞ energy source is magnetic energy size～（１－１０）x 104 ｋｍ Total energy 1029 -1032erg （~ １０5ー108 hydrogen bombs ） (Hida Observatory) Prominence eruption （biggest： June 4, 1946） Electro- magnetic Radio waves emitted from a flare (Svestka Visible 1976) UV 1hour time Solar corona observed in soft X-rays (Yohkoh) Soft X-ray telescope （1keV) Coronal plasma 2MK-10MK X-ray view of a flare Magnetic reconneciton Hα X-ray MHD simulation of a solar flare based on reconnection model including heat conduction and chromospheric evaporation （Yokoyama-Shibata 1998, 2001) A solar flare Observed with Yohkoh soft X-ray telescope （Tsuneta) Relation between filament (prominence) eruption and flare A flare observed at EUV Standard model (CSHKP model) （TRACE：~ 1MK plasma） (CSHKP=Carmichael-Sturrock-Hirayama-Kopp-Pneuman) Coronal Mass Ejections Coronal mass ejections （ＣＭＥ） (SOHO/LASCO) Velocity ~ 10 – 1000 km/s, mass ~ 1015 –1016 g coronal mass ejections (CMEs) and flares • Direct cause of geomagnetic storm is CME which lead to southward interplanetary magnetic field • About half CMEs are not associated with flares, but are associated with filament eruptions • Flares are not important for the Earth（Gosling’s flare myth 1993) ? • What is the relation between flares and CMEs ? Giant Arcade (not a flare because of very weak X-ray intensity) • On April 14, 1994 • K. Shibata reported through Yohkoh GBO mail that a large mass ejection may have occurred • Alan McAllister noted Shibata’s email and alerted possible occurrence of a big magnetic storm to Chicago power company • The company removed the big transformer (a few 100M$) for two days • A big magnetic storm actually occurred on April 16. • Because of removal of the transformer, it was not broken so the company saved a few 100M$ ! Interplanetary CME was also observed （McAllister et al. 1996) Relation between flare and coronal mass ejection (CME) Filament (prominence) and plasmoid are a part of CME Giant arcade, post flare arcade, post flare loop 2D-MHD model of coronal mass ejection (Shiota et al. 2005, ApJ) 2D-MHD model of coronal mass ejection (Shiota et al. 2005, ApJ 634, 663) edge? cavity core density t=100 SOHO/LASCO The numerical results reproduce the three-part structure. (see also Wu et al. Hu et al., Manchester et al. ,,,) Relation between flare and coronal mass ejection (CME) • Plasmas ejected from flare-region and ambient corona form a CME • Flares or Flare-like phenomena are always occurring below CMEs • There is no reason to distinguish flares and CMEs, i.e., both are a different aspect of the same physical phenomenon • It is not productive to discreminate flares and CMEs From now on, we shall use a term “flare/CME” based on unified view Remaining puzzles on flare/CME • What determines the speed of magnetic reconnection (energy release rate) ? • What fraction of released energy goes to energy of nonthermal particles ? • Energy storage mechanism • Triggering mechanism We need collaboration with Laboratory and magnetospheric Plasma physicists to solve these puzzles Observations of emerging flux triggering filament eruption (Feynman and Martin 1995) 2D-MHD simulation of Emerging flux triggering mechanism (Chen-Shibata 2000) Reconnection Associated with Emerging flux Breaks the equilibrium and Triggers the eruption of a large flux rope Two step reconnection model (Wang-Shi 1993, Chen-Shibata 2000, Kusano et al. 2004) reconnection (cancellation) associated with emerging flux sudden decrease in magnetic tension expansion of flux rope more energetic reconnection Emerging flux Solar wind Annual variation of sunspots and auroras Aurora frequency Coronal hole？ flare Sunspot Number Time (year) http://www.stelab.nagoya-u.ac.jp/ste-www1/naze/aurora/aurora27.html Coronal hole and high speed solar wind Corona during activity minimum What is the acceleration mechanism of high speed solar wind ? What is the origin of global solar magnetic field ? Alfven wave model One promising mechanism of high speed solar wind acceleration is Alfven waves, which may be produced by small scale jets and nano/picoflares (Parker 1991, Axford and McKenzie 1996, cf) Kudoh and Shibata 1999, Suzuki and Inutsuka 2005) (Shibata, Shimojo, Koutchmy, Kurokawa, Yamauchi-Moore) (Shimizu et al 2006) (Wang, Y-Sheeley, Mason-Pike, Fletcher) Filamentary jet produced by 3D patchy reconnection (Isobe et al. 2005 Nature) Halpha HIda EUV TRACE simulation observations Summary of “flare/CME” observations “flares” Size (L) Lifetime Alfven t/tA Mass ejection (t) time (tA) microflares 103 - 100- 1-10 sec ~100 jet/surge 104 km 1000sec Impulsive (1-3) x 10 min – 10-30 ~60-100 X-ray flares 104 km 1 hr sec plasmoid/ Spray Long duration (3-10)x 1-10 hr 30-100 ~100-300 X-ray (LDE) flares plasmoid/ 104 km sec prom. eruption Giant 105 - 10 hr – 2 100-1000 ~100-300 CME/prom. arcades 106 km days sec eruption Unified model (plasmoid-induced reconnection model: Shibata 1999) (a,b)： giant arcade, long duration/ impulsive flare (c,d) ：impulsive flares, microflares dE B2 B2 Energy release rate＝ ≈ V L2 ≈10−2 V L2 dt 4π in 4π A Future projects Japanese CAWSES-related space weather project • Grant-in-Aid for Creative Scientific Research (学術創成研究） of the Ministry of Education, Science, Sports, Technology, and Culture of Japan • Title: "The Basic Study of Space Weather Prediction“ • PI: K. Shibata (Kyoto Univ.) • recommended by Prof. Kamide • Term: 5 years (2005-2009) • Number of Researchers: 11 • Funding : 450 M yen / 5 years ~ 800k dollars/year Purpose of this project • The purpose of this project is to develop a physical model of solar-terrestrial phenomena and space storms as a basis of space weather prediction under international program CAWSES • To encourage close and effective collaboration between solar and geo- physicists Research Plan 1. Study of Energy Release on the Sun K. Shibata, S. K. Kato, S. Tsuneta, K. Kusano Kyoto/Hida obs and Solar B 2. Solar Wind Radio Observations and Modeling K. Fujiki Nagoya/STE Lab radio obs 3. Real Time Observations of Magnetosphere and Ionosphere and Space Weather Map Modeling T.Ogino, Y. Omura, T. Obara 4. Virtual Observatory (Numerical Modeling) M. Hoshino, M. Fujimoto, M. Ugai Solar-B Mission • Japan, USA, UK, ESA collaboration • Instruments – Solar Optical Telescope (SOT) – X-Ray Telescope (XRT) – EUV Imaging Spectrometer (EIS) • to be launched in 2006, September – Mission Lifetime: > 3 years • Scientific objective – coronal heating mechanism – elementary MHD processes such as magnetic reconnection HαObservations Flare Monitoring Telescope （ＦＭＴ）(Hida Obs., Kyoto Univ.) Full Sun Hα, Hα±0.8Å, 64mm aperture continuum image On video (2sec cadence) and CD-ROM(1min) with 4.2 arcsec pixel Images of flares and prominence eruptions are now open through http://www.kwasan.kyoto-u.ac.jp/Hida/FMT/ H αcenter Hα+－0.8 A Whole Earth H alpha Solar Observation CHAIN (Continuous H Alpha Imaging Network) project (leader : Prof H. Kurokawa) SMART (Solar Magnetic Activity Research Telescope) at Hida Observatory of Kyoto University, 2003 – observing full Sun Halpha and vector magnetic fields every 1 minute To observe energy storage and triggering consisting of 4 (two 25 cm and two 20 cm) telescopes Mechanism of flares and coronal mass ejections SMART (solar magnetic activity research telescope) H alpha image Vector magnetic field Discovery of Triple Moreton Waves in one flare (Narukage et al. 2006) High-resoluble observation of Moreton wave with Hida/SMART of Kyoto Univ H alpha -0.5 A running difference images of H alpha - 0.5 A Triple Moreton Waves 44 (Narukage et al. 2006) st 25–50 KeV •1wave (~460 km/s) is caught up with 2nd wave (~740 km/s) to merge into one wave • Radio intensity 2GHz 4GHz increased when two waves merged • Similar phenomena are seen in Cannibalism CME (Gopalswamy et al. 2001) which reported radio intensity increase when merging CAWSES International Workshop on Space Weather Modeling (CSWM) November 14 to 17, 2006 Earth Simulator Center Yokohama, Japan. LOC-chair : K. Kusano SOC: J. Büchner, T. I. Gombosi, N. Gopalswamy, M. Hesse, J.U. Kozyra, K. Kusano (co-chair), J. Lin, T. Ogino, B. Sanahuja, K. Shibata (co-chair), S. T. Wu Summary • Flares and coronal mass ejections (CME) are a different aspect of the same physical phenomenon, and can be unified as flare/CME, in which magnetic reconnection play fundamental role. • Flares/CMEs are important for space weather during activity maximum, whereas high speed solar wind from coronal holes seem to be important in declining phase of activity cycle • Small scale jets and nano/pico-flares may be the source of Alfven waves which heat and accelerate high speed solar wind in coronal hole (=> grand unification of corona/wind/jet/flare/CME by reconnection mechanism ?) • Basic physics of reconnection, triggering and energy storage mechanisms are still puzzling. (=> emerging flux triggering ?).
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