1. NEMO ESSW3 SIDC http://sidc.be/nemo "To understand is to perceive patterns" ROB

2. NEMO ESSW3 SIDC EIT Wave Detector Motivation  EIT waves quantitative properties  Free propagation  Interaction with ARs Properties - Models NEMO software  Architecture  Recognition & Diagnostic, Catalogue in real time

3. NEMO ESSW3 SIDC Solar Eruptions in Real time Flares CMEs  “Gopalswamy” list  http:/sidc.be/cactus  SEC events at NOAA, SXI  SolarSoft events  B2Xflare

4. NEMO ESSW3 SIDC Importance of On-Disk Eruptions geoeffectivity SOHO is in the L1 Lagrange point in the Solar-Terrestrial System, and goes around the Sun simultaneously with the Earth. SOHO profits continuous view of the Sun.

5. NEMO ESSW3 SIDC FOV: 45 arcminFOV: 54 arcmin 1.67 R 2.36 R Typically (CME watch): Cadence: 12 min Central wavelength: 19.5 nm Cadence: 1 min Central wavelength: 17.5 nm

6. NEMO ESSW3 SIDC Space Missions: STEREO SECCHI: Sun-Earth Connection Coronal and Heliospheric Investigation  Solar and heliospheric imager suite  Instrument goal:  3-dimensional reconstruction  Tracking of CMEs from the Sun to the Earth  Partners: NRL (PI), NASA & Lockheed (USA), MPI (D), CSL (B), RAL (UK), ROB (B) Belgian participation:  CSL: hardware & testing (stray light) for the Heliospheric Imager  ROB: software (image processing, event detection) and data analysis http://stereo.nrl.navy.mil/

7. NEMO ESSW3 SIDC How does Eruption look like in EUV? “EIT wave” precursor Original ImageImage substructed from prevrious one Discovery: Thompson et al, 1998; On disk CME signatures: Biesecker & Thompson, 2002

8. NEMO ESSW3 SIDC To extract such a signal from noise Requires an advanced technological approach  Huge phenomenological diversity of events  Signal weakness on top of dynamical backgrounds Requires a new pattern recognition approach  methods for tracking solid objects do not apply,  regular properties of EIT waves classification -> to develop specifically tailored method.

9. NEMO ESSW3 SIDC NEMO version 5.00 in MATLAB 7 DETECTION of event occurrence DIMMING extraction from EUV image EIT WAVE extraction from EUV image Higher order moments technique (applied to EUV image pixels distribution) method to detect coherent large scale structure in white noise Progressive Growth of intensive dimming region Ring Analysis (for automatic calculation of radial velocity of the EIT wave) Angular-Ring Analysis (to quantify the angular rotation of EIT wave )

10. NEMO ESSW3 SIDC PROGRESSIVE BUILD-UP OF DIMMINGS a). The deep core of the dimmings together with noise; b). The basis from which we build up the rest of the dimmings; c). All regions of negative intensity d). Selected region of negative intensity, corresponding to the full size of the dimmings

11. NEMO ESSW3 SIDC Dimmings: Spatial properties 1. Dimmings are extracted rigorously, defined: Their area Integral and differential intensity; structure Assumption: dimming: simply connected propagating region. Filtering out of noise deforming the dimming. Region of dimming propagation is determined by building up of filtered section of intensive dimming. Building up is done by the adding to the deep cut the pixels that belong to the cut on the intensity level of std. dev. That keep the condition of simple connected region. final dimmings: 04:50 UT05:07 UT 05:24 UT 05:41 UT EIT wave 12/05/97 N E S W N E S W N E S W N E S W

12. NEMO ESSW3 SIDC EIT wave quantities will depend explicitly on: Distance from eruption center, i.e. length of r (defined on sphere) Direction of radius-vector  Special polar coordinate system: Center: eruption center. Radius vector on sphere. 1 st step: Definition of eruption center (most intensive area) A posteriori: All complex EIT waves found to be well described in polar coordinates FRONT EXTRACTION Basic principles Algorithms based on the principles:

13. NEMO ESSW3 SIDC m m Eruption Center into line Synhronous propagation of the peak in sectors FRONT EXTRACTION Extraction techniques Ring integral intensity into pixel Angular-Ring Analysis Ring Analysis

14. NEMO ESSW3 SIDC Peak propagation used for automatic definition of radial velocity FRONT EXTRACTION Ring analysis Example 1: (1/4) simple magnetic structure, free front propagation Extracted Front Evolution EIT Wave 12 May 1997(1/4)

15. NEMO ESSW3 SIDC Rotation of fronts ! Morphological similarities between fronts and dimmings! FRONT EXTRACTION Angular-Ring Analysis Example 1: (3/4) simple magnetic structure, free front propagation Hot loop overlap dimmings EC front Angular 3D Structure of EIT wave EIT Wave 12 May 1997 (3/4)

16. NEMO ESSW3 SIDC Integral front intensity Integral dimming intensity Angular-Ring Analysis FRONT EXTRACTION Example 4: (2/2) complex magnetic structure, restricted front propagation Dimmings and EIT front Integral Intensities EIT Wave 1 April 1997 -Integral intensity of propagating front grows in time (30 mn) symmetrically,,,with respect decrease of integral dimming intensity – regular peculiarity.

17. NEMO ESSW3 SIDC EIT Wave 12 May 1997 Integral intensity on concentric circles around flaring center at 4 successive times Space weather applications Real-time halo CME alerts: Source identification Faint undetected halos Tool for science investigation First systematic event catalog Coronal seismology Physical nature of waves: fast/slow MHD? dimmings: field opening, transient coronal hole ? Difficulties: phenomenological diversity weak and faint events Observed properties: Width of the wavefront grows quasi quadratically in time Dimming boundary contiguous to inner wavefront edge Correlation of wave structure with associated dimming Energy supply to EIT wave fronts comes from dimmings Extraction

18. NEMO ESSW3 SIDC 2. Geometrical Extraction (1/3) dimmings EIT wave front Eruption center 1.Solar demisphere projected on the plane during an EIT wave event 2.8 vertical cross-section from EC, radially CROSS-SECTION

19. NEMO ESSW3 SIDC Under condition of free propagation rotation of EIT wave fronts observed regulary. Sense of rotation is different in the two solar hemispheres FRONT EXTRACTION Angular-Ring Analysis Example 1: simple magnetic structure, free front propagation dimmings EC front dimmings EC front Angular 3D Structure of EIT wave

20. NEMO ESSW3 SIDC

22. 14:12 - 14:00 -UT 14:21-14.00 UT 14:35 - 14:00 UT 14:53 - 14:00 UT S WE S WE RELATION BETWEEN EIT WAVE FRONT & DIMMING NONCIRCULAR PROPAGATION OF EIT WAVE 07/04/97 S WE S WE d1d1 d2d2 d3d3 d4d4 14:12 - 14:00 -UT 14::21-14.00 UT ANISATROPIC EIT wave structuresDimmings Integral intensity of each half circle in time SE NW Velocity of structure propagation is different in SE and NW. Dimmings adjoins fronts in each directions.

23. NEMO ESSW3 SIDC 07 April 1997

24. NEMO ESSW3 SIDC Phase velocities of linear waves, absence of slow mode at θ = π / 2.

25. NEMO ESSW3 SIDC Fast mode moving upwards and slow downwards time Spatial coordinate Density profile after cylindrical source explosion (Sedov like solution) 3. Validation (1/2)

26. NEMO ESSW3 SIDC 4. 3. 2. 1. 15:18:38 1997/04/01 12:05:23 1997/04/01 09:24:33 1997/04/01 06:22:001997/04/01 LASCO CME 1. 2.3. 4.WHERE? ERUPTION MEASURE A. Detection

27. NEMO ESSW3 SIDC Centered moment of order k: experimental: PDF(x i ) theoretical: Measure of PDF asymmetry: - Skewness Gaussian:  1=  2=0  1=0,  2>0 DETECTION: method flatness: - Kurtosis  1>0,  2>0  1,  2 >> 0 computed for pixels distribution of EUV image could be indicators of large scale coherent structures: for a Gaussian distribution  1 =  2 = 0 Higher-order Moments

28. NEMO ESSW3 SIDC 3. Validation (2/2)

29. NEMO ESSW3 SIDC Example of Daily List

30. NEMO ESSW3 SIDC Architecture NEMO 5.0 Matlab 7.0 Detection Real Time Catalog Geometrical Extraction Validation SOHO scan catalog SOHO-STEREO- SWAP (onboard)

31. NEMO ESSW3 SIDC Conclusion (1/2) SIDC new product (sidc.be/nemo)  Real-time catalog  Monthly scan STEREO Waves

32. NEMO ESSW3 SIDC  detects only eruptions, not flares.  can build on-disk SP.W. event catalog with SWAP and SECCHI.  extraction technique brings new insight on events.  is able to sort out the SOL.O. SDO dataflow ~TB/day.  Onboard realisation (CORONAS-F) Conclusion (2/2)

33. NEMO ESSW3 SIDC Thanks To Barbara Thompson for 1997-1998 EIT wave catalog To SIDC preview web, Cactus, B2X team To ESA, NASA, SECCHI/STEREO/NRL Orleans- LPCE, Meudon Obsrevatory, Florence University (European network)

34. NEMO ESSW3 SIDC