Flare-Associated Oscillations Observed with NoRH Nobeyama Symposium 2004 : 2004/10/26 Flare-Associated Oscillations Observed with NoRH Ayumi Asai (NSRO)

Flare-Associated Oscillations Quasi-Periodic Pulsation (QPP) 1980-06-07 flare Nakajima et al. 1983 Kiplinger et al. 1983 Kane et al. 1983 Both m-wave and HXR show quisi-periodic oscillation (QPP) oscillation period : ~8sec typical time scale : ~Alfven transit time X-rays microwave 17GHz

What are These? QPP nonthermal emission (in microwave and HXR) efficiency of particle acceleration is modulated periodically QPP period : ~ Alfven transit time scale physical parameters should be determined from observation! Which mode determines the periodicity? Loop oscillation (sausage, kink, …) Particle acceleration process?

1998 November 10 Flare 1998-11-10 Flare (C7.9) @NOAA8375 Asai et al. 2001/Grechnev et al. 2002 QPP! NOAA 8375 1998-11-10 Flare (C7.9) @NOAA8375 Multi-wavelength observation : NoRH, NoRP, SXT, HXT, MDI

QPP in Microwave (only) source A shows QPP Oscillation period ~ 6.6 sec source A source B total NoRH 17GHz source A source B

Geometrical Properties Loop-loop interaction Flare site = source B A B source A Flare Loop negative image source B

QPP in Microwave and HXR HXR light curves also show QPP m-wave peak slightly delay from HXR peak (~0.6s) ~ traveling time of nonthermal electrons Length of faint loop : 50,000 km velocity of nonthermal particle ~100,000 km/s traveling time : 50,000 / 100,000 = 0.5 s

Physical Values SXT temperature analysis (source B) T : 9.4 MK n : 4.5×1010 cm-3 MDI + potential field approx. B : 300 G A B negative image source A Flare Loop source B

Physical Parameters (1) flare loop / flare kernel ~ length : 16,000 km ~ width : 6,000 km temperature : 9.4MK density : 4.5×1010 cm-3 magnetic field : 300 G sound velocity : 360 km/s Alfven velocity : 3,100 km/s (2) (1) c.f. (2) faint loop : ~50,000 km

Physical Parameters (1) flare loop / flare kernel ~ length : 16,000 km ~ width : 6,000 km sound velocity : 360 km/s Alfven velocity : 3,100 km/s Alfven transit time: Along the loop : 5.1 s Across the loop : 1.9 s Acoustic transit time : Along the loop : 44 s Across the loop : 17 s (2) (1) observed period ~ 6.6 s Alfven transit time along the loop (5.1 s) is the most similar

Alfven transit time (s) Statistical Study Kamio et al. 2004 Period ~ Alfven transit time scale along the loop Date velocity (km/s) Alfven transit time (s) Sound transit time (s) Obs. P(sec) VA VS L W 1998-11-10 3100 360 5 2 44 17 6 1997-12-01 1200 430 10 - 23 2001-04-24 2500 410 8 0.8 49 4.9 2001-09-10 1600 13 1.9 7 16

2000-01-12 Event Melnikov, et al. 2002 Foot 1 Loop top 14 – 17 s image : 17 GHz orange cont. : 34GHz brown cont. : HXT M2 Foot 2 loop length : 25,000 km Fourier power spectra Radio flux variation

Which Mode Determines QPP? Period of QPP ~ Alfven transit time scale MHD fast mode kink mode sausage mode

Kink Mode Oscillation TRACE P ~ 300 sec tkink ~ L/CA - Aschwanden et al. 1999 - Nakariakov et al. 1999 P ~ 300 sec tkink ~ L/CA

Kink Mode?? In the case of m-wave QPP : tkink ~ 5 s L : 16,000 km CA : 3,100 km ~observation (P ~ 6 s) Is it possible for flare loop in high pressure? A B negative image

Sausage Mode Oscillation - Nakariakov et al. 2003 - Aschwanden et al. 2004 Previous estimations: External medium, finite wave length  or k=kc

Radio Pulsation (no imaging) Aschwanden et al. 1987, 2002, etc… clearer oscillation in radio oscillation periods : P = 0.01  1000 s Culgoora radio spectograph 1972/05/16 flare McLean & Sheridan (1973) Pulsations at 230 MHz, period = 4.28 ± 0.01 s

Sausage Mode?? Parameters of loop CA0 = 440 km/s CAe = 3,500 km/s L = 25,000 km  PGSM = 2L/Cp ~ 2L/CAe P~15 s ~ observation ! Melnikov et al. 2002 Nakariakov et al. 2003

Sausage Mode?? L : 16,000 km T : 9.4 MK n : 4.5×1010 cm-3 B : 300 G CA0 = 3,100 km/s CAe = ?? km/s PGSM < 2L/CA0 ~ 10 s OK for the case that k is large enough A B negative image

Loop OscillationParticle Acceleration Loop oscillation modulates the efficiency of particle acceleration? reconnection region (energy release site) as itself oscillates!?

Loop OscillationParticle Acceleration Tsuneta and Naito (1998) Shock acceleration (Tsuneta and Naito 1998) Coalescence instability (Tajima et al. 1987) How loop oscillation modulates particle acceleration? flare-loop Loop oscillation

Summary & Conclusions Flare-associated oscillations are observed with NoRH Oscillation period ~ Alfven transit time scale Oscillation period is also explained with kink-mode or sausage-mode (not fixed) Coronal Seismology Loop oscillation modulates the efficiency of particle acceleration How?

Thank you!

Oscillation Period (Auto-Correlation) using NoRP 9.4GHz data, we determined the oscillation period (auto-correlation function) ~ 6.6 sec 6.6 sec

Cross Correlation Cross-correlation function between HXR and m-wave light curves m-wave peaks delay ~0.6 sec ~0.6 sec source A HXT source B

QPP in microwave and HXR HXR light curves also show QPP m-wave peak slightly delay from HXR peak (~0.6s) ~ traveling time of nonthermal electrons Length of faint loop : 50,000 km Time delay : 0.6 s length of effective electron path: 150,000 km

Coronal Magnetic Field MDI 1998-11-06 SOHO/MDI potential field approximation (MDI data of 1998/11/06)  ~ 350 G flare loop rotation

No m-wave QPP at Source B No QPP in microwave at source B Emission from thermal plasma (thermal-Bremsstrahlung) is dominant caused by 1st burst

Kink Mode?? In the case of m-wave QPP : tkink ~ 5 s L : 16,000 km CA : 3,100 km ~observation (P ~ 6 s) Is it possible for flare loop in high pressure?

Slow Mode Oscillation by SUMER Wang et al. 2002 Ofman et al. 2002 2001-03-09 event (not flare) SUMER slit SUMER slit 200 arcsec Yohkoh/SXT TRACE 195A Fe XIX (6  106 K)