NEMO ESSW3 SIDC

http://sidc.be/nemo

"To understand is to perceive patterns"

ROB

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

NEMO ESSW3 SIDC

Solar Eruptions in Real time

Flares

CMEs

“Gopalswamy” list http:/sidc.be/cactus

SEC events at NOAA, SXI SolarSoft events B2Xflare

NEMO ESSW3 SIDC

Importance of On-Disk Eruptionsgeoeffectivity

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.

NEMO ESSW3 SIDC

FOV: 45 arcmin FOV: 54 arcmin

1.67 R

2.36 R

Typically (CME watch): Cadence: 12 minCentral wavelength: 19.5 nm

Cadence: 1 minCentral wavelength: 17.5 nm

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/http://stereo.nrl.navy.mil/

NEMO ESSW3 SIDC

How does Eruption look like in EUV?

“EIT wave”precursor

Original Image Image substructed from prevrious one

Discovery: Thompson et al, 1998; On disk CME signatures: Biesecker & Thompson, 2002

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.

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 )

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 intensityd). Selected region of negative intensity, corresponding to the full size of the dimmings

NEMO ESSW3 SIDC

Dimmings: Spatial properties1. Dimmings are extracted rigorously, defined:

•Their area

•Integral and differential intensity; structureAssumption: 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 UT 05:07 UT

05:24 UT 05:41 UT

EIT wave 12/05/97N

E

S

W

N

E

S

W

N

E

S

W

N

E

S

W

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. 1st 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:

NEMO ESSW3 SIDC

mm

Eruption Center

into

lin

e

Synhronous propagation of the peak in sectors

FRONT EXTRACTION

Extraction techniques

Ring integral intensity

into

pix

el

Angular-Ring Analysis Ring Analysis

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)

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 waveEIT Wave 12 May 1997 (3/4)

NEMO ESSW3 SIDC

Integral front intensity

Integral dimming intensity

Angular-Ring Analysis

FRONT EXTRACTION

Example 4: (2/2)complex magneticstructure, 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.

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

NEMO ESSW3 SIDC

2. Geometrical Extraction (1/3)

dimmings

EIT wave front

Eruption center

1.1. Solar demisphere projected on the planeSolar demisphere projected on the plane

during an EIT wave event during an EIT wave event 2.2. 8 vertical cross-section from EC, 8 vertical cross-section from EC,

radiallyradially

CROSS-SECTION

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

NEMO ESSW3 SIDC

NEMO ESSW3 SIDC

NEMO ESSW3 SIDC

14:12 - 14:00 -UT

14:21-14.00 UT14:35 - 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

d1

d2d3

d4

14:12 - 14:00 -UT

14::21-14.00 UT

ANISATROPIC EIT wave structuresDimmingsIntegral 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.

NEMO ESSW3 SIDC

07 April 1997

NEMO ESSW3 SIDC

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

NEMO ESSW3 SIDC

0 0.2 0.4 0.6 0.86

8

10

12

14

Fast mode moving upwards and slow downwards

time

Spatial coordinate

Density profile after cylindrical source explosion (Sedov like solution)

3. Validation (1/2)

NEMO ESSW3 SIDC

4.

3.

2.

1.

15:18:381997/04/01

12:05:231997/04/01

09:24:331997/04/01

06:22:00 1997/04/01

LASCO CMELASCO CME

1.1.

2.2. 3.3.

4.4.

WHERE?WHERE?

ERUPTION MEASUREERUPTION MEASURE

A. Detection

NEMO ESSW3 SIDC

Centered moment of order k:

experimental:PDF(xi)

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

NEMO ESSW3 SIDC

3. Validation (2/2)

NEMO ESSW3 SIDC

Example of Daily List

NEMO ESSW3 SIDC

Architecture

NEMO 5.0NEMO 5.0Matlab 7.0Matlab 7.0

DetectionDetection

Real Time CatalogReal Time CatalogGeometrical Geometrical ExtractionExtraction

ValidationValidation SOHO scan catalogSOHO scan catalog

SOHO-STEREO-SOHO-STEREO-SWAP (onboard)SWAP (onboard)

NEMO ESSW3 SIDC

Conclusion (1/2)

SIDC new product (sidc.be/nemo)Real-time catalog Monthly scan

STEREO Waves

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)

NEMO ESSW3 SIDC

Thanks

To Barbara Thompson for 1997-1998 EIT wave catalogTo SIDC preview web, Cactus, B2X teamTo ESA, NASA, SECCHI/STEREO/NRLOrleans- LPCE, Meudon Obsrevatory, Florence University (European network)

NEMO ESSW3 SIDC