Science with Facilities at ARIES

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1 Science with Facilities at ARIES Wahab Uddin Aryabhatta Research Institute of Observational Sciences(ARIES), Nainital ARIES

2 Science Goals with ARIES Solar Observations: [1] Ground based observations of flare, its energy build-up and energy release. [2] Observations of the driving mechanisms of solar eruptions. [3] Space weather [4] Waves in the lower solar atmosphere. [5] Complementary observations w.r.t. space-borne observations.

3 Existing Solar observing facilities at ARIES 15 cm Coude Solar tower telescope equipped with: H-alpha filter, 0.5 Å PB 1KX1K, 13 µ 2, 16 bit, 10 MHz read out rate back illuminated, frame transfer EM CCD camera. Spatial resolution: ~0.6 arc-sec/pixel Temporal resolution: ~100 ms for full frame and higher for small ROI It works in two modes: 1. Normal mode. 2. Automatic flare mode

4 Schematic drawing of 15 cm Coude refractor Solar Tower Telescope ARIES

5 Important Results from ARIES Observations 10 March 2001 extremely Impulsive 1B/M6.7 unusual flare This is a very impulsive flare, which occurred in NOAA active region 9368 (N27 W42). The flare was observed with Solar Tower Telescope at ARIES, Nainital, Yohkoh/SXT and HXT, Nobeyama (NoRH) and polarimeter (NoRP) and SOHO/EIT/LASCO. Emphasis is put on the temporal,spatial correlation at different wavelengths and energetic of this flare.

6 Evolution of NOAA 9368 FROM 7-10 MARCH Top and middle rows are H center and off band 0.8 Å images. Bottom row represents SOHO/MDI magnetograms. FOV is 240x195 arc-sec 2

7 10 March 2001 extremely Impulsive 1B/M6.7 unusual flare

8 H flare movie of impulsive flare on 10 March 2001

9 HXR H band images (contour) of the flare during the impulsive phase. HXR source shows rotation in the clockwise direction. This is a unique feature of this flare.

10 Energy buildup through the magnetic flux cancellation in the flaring region. We report for the first time the rotation of HXR and Hα sources in the 10 March, 2001 solar flare. We propose two possibilities for Rotation in HXR and Hα sources one is may be due to the asymmetric progress of magnetic reconnection site another is change of peak point of electric field. The 10 March, 2001 solar flare has very hard spectrum (power law index ~ 2, near the physical limit) and it does not have broken power law, which many flares do. This is the indicator that this flare is in low corona. We observed an unusual feature in 10 March, 2001 solar flare is that this is extremely impulsive/ compact flare but was associated with fast CME and type II radio burst, which are not general characteristics of an impulsive solar flares.

11 Eruption of large helical prominence on 21 April 2001

12 Eruptive solar prominence of 21 April, 2001 The study of the geometrical parameters of the prominence of 21 April, 2001, reveals that the prominence has erupted although its twist falls into the stability regions of the ideal MHD model by Vrsnak (1990c). The most probable explanation for the present eruption seems to be that the magnetic reconnection below the erupting flux rope played an important role in the dynamics of eruption. The spatial and temporal correlation between CME and prominence is found to be good. Since no flare or radio burst was associated with the eruption, the present analysis supports the idea that neither radio bursts not flare are necessary for CME production, though generally they have good association with CMEs. It is concluded that the energy stored in the prominence ( 2.8x10 32 ergs) is sufficient to power both the CMEs ( the combined energy of both CMEs being 2.5x10 31 ergs).

13 4B/X17.2 Flare on 28 October, 2003

14 Ribbon Polarity R1 = -ve R2 = +ve R3 = -ve R4 = +ve 12-Nov-11 4B/X17.2 Flare on 28 October, 2003

15 4B/X17.2 flare on 28 October 2003 (a) (b) (c) One of the largest flare ever recorded. Energy buildup through flux emergence. Estimated energy stored in the sigmoid filaments is ~10 34 ergs which is more than sufficient to trigger this mega flare; associated with full halo CME (10 33 ergs) and related phenomena. (d) Involves large-scale quadrupolar reconnection process. Filament eruption supports breakout model. (e) Ribbon separation speed ~70 km s -1 (f) Produced co-spatial Doppler ribbons in the photosphere. (g) Produced all the energetic phenomena which one can expect from the major flares.

16 Eruption of a filament and flares on 18 November 2003

17 (i) C3.8 flare (a) Hα Observations 12-Nov-11 IHY Workshop, ARIES, Nainital, India

18 (ii) M3.2 and M3.9 flare H-alpha Evolution of M3.2 (left) and M3.9 (right) solar flares.

19 Flares and filament eruptions H images from ARIES. Different segments of filament material encircle the main negative polarity apparent large circular-shaped single filament. Portions of the filament (F, F2a) are not visible after Flare 1 and 2. The southern portion (F2b) is erupting.

20 18 November, 2003 flare events The geoeffective magnetic cloud (MC) of 20 November 2003 was associated with the 18 November 2003 solar active events in previous studies. In some of these, it was estimated that the magnetic helicity carried by the MC had a positive sign, as did its solar source, active region (AR) NOAA We show that the large-scale magnetic field of AR has a negative helicity sign. Since coronal mass ejections (CMEs) are one of the means by which the Sun ejects magnetic helicity excess into interplanetary space, the signs of magnetic helicity in the AR and MC must agree. Therefore, this finding contradicts what is expected from magnetic helicity conservation. However, using, for the first time, correct helicity density maps to determine the spatial distribution of magnetic helicity injections, we show the existence of a localized flux of positive helicity in the southern part of AR We conclude that positive helicity was ejected from this portion of the AR leading to the observed positive helicity MC.

21 . Interaction of H filaments and change in direction during November, 2003

22 Changes of filament orientation, which is the signature of magnetic Reconnection ARIES

23 Evolution of 1N/M1.4 Flare in Hα 20 th November 2003 I Flare First flare starts with two filaments reconnection. ARIES

24 Evolution of 2B/M9.6 Flare in Hα Second impulsive flare starts with two filaments reconnection and dark cusp formed during impulsive/ maximum phase. II Flare ARIES

25 Eruption of a filament and flare on 20 November 2003

26 Rotation of opposite polarity spots play important role in filament activation/interaction

27 20 November, 2003 flare events Results Many pieces of evidence supporting the magnetic reconnection model of flares were found by recent space-craft observations We found that the two twisted filament system plays main important role in the occurrence of these flares. These filament systems change their directions/connectivity with each other, which indicate the signature of the magnetic reconnection before triggering the flare. Generally the reconnection starts in the upper atmosphere of the Sun i.e. from corona but the reconnection can be seen very clearly in the Chromosphere also which we have noticed in the H-alpha observations. Both flares show the similar evaluation pattern. The second flare was very energetic which clearly shows very dark cusp type structure of the filament above the flare. This flare produces type II radio bursts and CMEs. Cusp Speed~64.81 km/sec Filament speed ~6.6 km/sec ARIES

28 Study of Waves : Multiple Sausage Observations in the Cool Post Flare Loop The loop system is also visible in higher temperature lines, e.g.,fe IX/ X 171 EIT/SOHO : This implies that the energy balance is not occurring, and there is temporal change of density, temperature etc. This also implies that the loop is not in hydrostatic equilibrium as we are aware. Hence, the hydrostatic condition of upper or lower solar atmosphere is only a limiting case. Selected Loop H-alpha 6563 Image obtained using ARIES Tower Telescope May 2, 2001 AR 9433 (N15, W 88),01:00:52 UT 01:58 :28 UT ---> Post Flare Loop System

29 Power Spectrum Near Loop Apex Power Spectrum Near Loop Footpoint Observed Loop Length ~ 35 Mm, Loop Width ~ 4 Mm The phase speed will be ~ 2L/P ~ 109 km/s The speed is much higher than the sound speed at this low temperature. Hence, we suggest the fast tubular sausage modes in this cool loop. Period Ratio P 1 /2P 2 = 0.84.

30 Results and Discussions Only very dense loops can support the non-leaky sausage mode in the estimated length and width (Nakariakov et al. 2003, A&A, 412, L7). The post flare loops have usually very high density contrast between , and thus our selected loop is also an over dense postflare loop. The selected loop is cool postflare loop, and density ratio falls in the expected range. hence, the trapped sausage mode may occurs in the loop, however, wave leakage can not be ruled out. Shift of P1/P2 ratio from 2.0 can be due to the density stratification or magnetic field stratification in such loops, similarly as found by Van Doorsselaere et al. (2007, A&A, 473,959), Verth & Erdelyi (2008, A&A, 486, 1015) for kink waves. The estimated density scale height for the observed parameters is ~ 6.0 Mm These results are the confirmations of the findings published in our one paper in (MNRAS, 388, 1899) by A.K. Srivastava, T.V. Zaqarashvili, W.Uddin, B.N. Dwivedi, and Pankaj Kumar. However, the local plasma properties vary from loop to loop in the post-flare loop system. A theoretical test has been successfully performed by Inglis et al. (A&A, 2009) for our mail observational findings published in MNRAS.

31 Recent Observation at ARIES

32 Hα -3.0 Å Hα -2.0 Å Hα -1.0 Å Hα 0.0 Å 11:36:18 UT 11:38:46 UT 11:41:24 UT 11:45:17 UT 11:45:17 UT 11:52:54 UT 11:52:54 UT 11:56:17 UT Post flare loops of X1.4/2N flare on 22 September, 2011

33 Hα -1.5 Å Hα 0.0 Å 01:45:22 UT M4.4/SF 02:32:59 UT Hα 0.0 Å Hα 0.0 Å M7.4/2N 04:52:24 UT M7.4/2N 04:52:24 UT M4.4/SF and M7.4/2N flares on 25 September, 2011

34 Hα -1.5 Å Hα 0.0 Å 02:24:30 UT 02:37:36 UT Active Region NOAA on 28 September, 2011 The study of flares from NOAA is under progress

35 Future Plan Upgradation of solar observing facilities at ARIES to carry out complementary/ supplementary observations to the upcoming solar observing facilities i.e. MAST, Aditya-1 and NLST etc. for active collaborations

36 Thanks