Coronal Dynamics - Can we detect MHD shocks and waves by Solar B ? K. Shibata Kwasan Observatory Kyoto University 2003 Feb. 3-5 Solar B ISAS

Introduction Recent space observations such as Yohkoh, SOHO, TRACE have revealed various evidence of magnetic reconnection and common properties in flares/CMEs, leading to unified view of flares/CMEs. Impulsive flares LDE flares Giant arcades (CMEs)

Plasmoid (flux rope) ejections impulsive flares ~ 10^9 cm LDE flares ~ 10^10 cm CMEs (Giant arcades) ~ 10^11 cm Unified model

Solar Jets H alpha jets (surges) EUV macrospicules EIT jets LASCO jets CDS spinning jet (Pike&Mason) H alpha spinning jet (Kurokawa/Canfield) EIT-LASCO jet (Wang, Y. M.)

Unified model of flares and jets (Shibata 1999) (a,b) ： LDE/impulsive flares and CME/plasmoid (c,d) ： microflares and jets

Unified model of flares and jets (Shibata 1999) (a,b) ： LDE/impulsive flares and CME/plasmoid (c,d) ： microflares and jets Fast shock Slow shock Fast shock Alfven wave Should be tested by Solar B

Can we detect MHD shocks/waves by Solar B ? -- today’s talk : related new studies Modeling of Peculiar Mass Ejections Associated with Giant Cusp Arcade - Fast and Slow Mode MHD Shocks are Identified !? Shiota et al. (2003) Coronal Heating by Alfven Waves - nanoflare is not reconnection, but propagating MHD shocks !? Moriyasu et al. (2003) Moreton wave => Narukage et al. (next talk)

Modeling of Peculiar Mass Ejections Associated with Giant Cusp Arcade - Fast and Slow Mode MHD Shocks are Identified !? Shiota et al. (2003)

Slow and Fast mode MHD shocks have not yet been identified no clear evidence of slow and fast mode MHD shocks in SXT images Impulsive flares LDE flares

Giant Arcades are found at the base of Coronal Mass Ejections (April 14, 1994) (Jan , 1992)

Giant Cusp Arcade and Peculiar Mass Ejection (Hiei, Hundhausen, & Sime 1993) Jan 24, 1992

Ejection (Y-shaped structure) velocity 30 ～ 40 km/s

Simulations (Shiota et al. 2003; extention of Chen-Shibata model, including heat conduction) Normalization units

Predicted soft X-ray intensity （ SXT/Al.1 ）

Y-shaped ejection

What is Y-shaped structure ? Y-shaped structure = Slow Shock ＆ Fast Shock

Observations : height-time diagram the top of cusp the center of Y-shape

Simulations : height-time diagram Triangle = Y-shaped structure = slow and fast shocks

Effect of Angle between arcade axis and line-of-sight SXT/Al.1 09:20 Angle=20° Angle=0° 0<DN/s<200 0<DN/s<50 Assume uniform arcade with length of 10^5 km Angle=10°

XRT/Thin Al mesh SXT/Al.1XRT/Al mesh Line-of-sight distance is 10^4 km

XRT/Thin Al poly SXT/Al.1XRT/Al poly Line-of-sight distance is 10^4 km

XRT/Thin Ti poly SXT/Al.1XRT/Ti poly Line-of-sight distance is 10^4 km

Intensity distribution XRT/Thin Al mesh Depth=10^5 km 、 angle=20° exposure time Count=100 →10 ～ 15 sec DN/s/pix pix

Coronal Heating by Alfven Waves - nanoflare is not reconnection, but propagating MHD shocks !? Moriyasu et al. (2003)

Motivation Kudoh & Shibata (1999), Saitoh et al. (2001) successfully developed Alfven wave model of spicules and nonthermal line width in corona Yokoyama (1998), Takeuchi & Shibata (2001) found that reconnection generate Aflven waves efficiently SOHO revealed magnetic carpet, suggesting ubiquitous reconnection in the photosphere

Photospheric reconnection (or turbulent convection) => Alfven waves => coronal heating ? we performed the 1.5D-MHD numerical experiment including heat conduction and radiative cooling photosphere km Initial condition T = 10 4 K = uniform based on 2D-MHD simulation of emerging flux （ Shibata et al.1989) Twist flux tube randomly 1 km/s

Simulation Results (propagation of nonlinear Alfvén waves)

Simulation results (temperature distribution)

Temperature distribution

Alfvén wave Nonlinear effect Compressional wave (slow mode & fast mode) Shock heating shock formation Heating mechanism

Average coronal temperature vs photospheric velocity amplitude

“Observations” of simulation results Yohkoh/SXT TRACE (171Å) => flare-like brightening SXT intensity is too low TRACE(EUV) intensity is comparable to observed intensity for 10^5 km coronal loop 1998/6/4 TRACE (171Å)

Statistics of “flare” (shock heating) peak frequency distribution show power law ↓ intermittent heating due to MHD shocks generated by Alfvén waves might be observed as microflares or nanoflares ! Index:-1.6 ~ -2

Conclusion 1.Unified (reconnection) model of flares and jets predict generation of slow and fast mode MHD shocks as well as Alfven waves. 2.Slow and fast mode MHD shocks can be identified in Y-shaped mass ejection above giant cusp arcade (Shiota et al. 2003) 3.Spicules, nonthermal line width, and coronal heating are all explained by Alfven waves if its velocity amplitude > 1 km/s in the photosphere. (Kudoh-Shibata 1999, Saitoh et al. 2001) 4.Alfven waves can be dissipated through nonlinear mode coupling with fast and slow mode MHD waves/shocks. MHD shock heating is flare-like and might be observed as microflares or nanoflares (Moriyasu et al. 2003). => Should be tested by Solar B

fast shock & slow shock β<1 fast wave ： Va slow wave ： Cs in the present case, these are weak shocks fast shock ~ fast wave ~ Va slow shock ~ slow wave ~ Cs Va ~ 250 km/s Cs ~ 120 km/s

Alfven wave model of spicules: 1.5D-MHD simulation (Kudoh-Shibata 1999)

3. Are sufficient energy flux carried by Alfven waves into corona ? (Saitoh, Kudoh, Shibata 2001)

Energy flux transported to the corona by Alfven waves Nonthermal Coronal Line width