Temporal and Frequency Variations of Flares observed by LYRA onboard of

PROBA2

Joe.Zender@esa.int (1)

B. Foing (1), D. Vagg(2), M. Dominique(3), I. Dammasch(3), M. Mierla(3) and the LYRA Team

(1)Science and Robotic Exploration Directorate, ESA, ESTEC, Noordwijk, The Netherlands(2)Waterford University, Waterford, Ireland(3) Royal Observatory of Belgium, SIDC, Brussels, Belgium

Outline

INTRODUCTION TO PROBA2

INTRODUCTION TO LYRA

TEMPORAL ANALYSIS OF CX FLARE ON 2010-06-15T

FREQUENCY ANALYSIS OF SAME FLARE

• INTRODUCTION TO WAVELET

• WAVELET ANALYSIS OF LYRA DATA

• FLARE RESULTS

CONCLUSION AND DISCUSSION

Discussion of Solar activities on 15 June 2010 based on temporal and frequency analysis of Zirconium (1-20nm) and Aluminum (17-80nm) channels of the LYRA instrument flown on board of

PROBA

LYRA EUV channels are suitable for flare analysis in time domain. Some flares show oscillations during initial flare phase, e.g. 0.1Hz and 0.014Hz for the 2010-06-15 flare

PROBA2 – in a nutshell

Technology Demonstrators17 technological demonstrators: BepiColombo star tracker (Galileo Avionica), Digital Sun Sensor (TNO), GPS Receiver (Alcatel, DLR), Laser Reflector (ESTEC), …

Built as part of ESA’s PRoject for OnBoard Autonomy Launched on 2nd November 2010 into Earth – sun synchronous - orbit

Ground Segment- Mission Operations Centre located at Redu- ~10 daily passes from Redu or Svalbard (S-band)Spacecraft

- Dimension: 80x70x60cm- Mass: 120kg, of which 35 for payload- Highly autonomous- ~720km altitude- sun-pointing

Flexible commanding at Science Centre (P2SC)Data processing at P2SC within 30-45min after data reception.

Large Yield Radiometer (LYRA)

3 Units, each with 4 channels: Lyman-Alpha 121.6nm, Herzberg 200-220nm, Aluminum 17-80nm, Zirconium 1-20nm

Unit 2 is operated continuously at 20 Hz (100Hz demonstrated), Unit1 and Unit3 for calibration purpose and dedicated campaigns

Spectral Response of LYRA EUV Channels

Measured spectral transmittance of the Al (157.9 nm thick) and the Zr (141.3 nm thick) filters from Luxel corp. between 1 and 30 nm

Measured spectral transmittance of the Acton Research corp. filters: Lyman-α filters (N122, XN122) and 210-B Herzberg filter between 110 nm and 2600 nm

From Astronomy & Astrophysics manuscript no. aa13089-09, November 27, 2009BenMoussa et al, “Pre-Flight calibration of LYRA, the solar VUV radiometer on board PROBA2”

Events on 13 June 2010

Several flares were observed by LYRA2010/06/13 00:06:00-00:26:00 B8.8 1079 2010/06/13 02:28:00-02:35:00 B4.6 10792010/06/13 05:30:00-05:44:00 M1.0 10792010/06/13 06:08:00-06:13:00 C1.2 10812010/06/13 06:55:00-07:00:00 B5.3 10812010/06/13 07:05:00-07:10:00 C1.2 10802010/06/13 07:31:00-07:38:00 C1.2 10792010/06/13 08:06:00-08:16:00 C1.2 10812010/06/13 09:41:00-09:48:00 C1.7 10812010/06/13 10:47:00-10:55:00 C1.5 10812010/06/13 12:24:00-12:29:00 B4.3 10812010/06/13 13:20:00-13:26:00 B2.5 10812010/06/13 14:24:00-14:30:00 B2.4 10812010/06/13 15:45:00-15:59:00 B4.2 10812010/06/13 18:10:00-18:17:00 B1.8 1081

Events on 13 June 2010

Several flares were observed by LYRA2010/06/13 00:06:00-00:26:00 B8.8 1079 2010/06/13 02:28:0002:35:00 B4.6 10792010/06/13 05:30:00-05:44:00 M1.0 10792010/06/13 06:08:00-06:13:00 C1.2 10812010/06/13 06:55:00-07:00:00 B5.3 10812010/06/13 07:05:00-07:10:00 C1.2 10802010/06/13 07:31:00-07:38:00 C1.2 10792010/06/13 08:06:00-08:16:00 C1.2 10812010/06/13 09:41:00-09:48:00 C1.7 10812010/06/13 10:47:00-10:55:00 C1.5 10812010/06/13 12:24:00-12:29:00 B4.3 10812010/06/13 13:20:00-13:26:00 B2.5 10812010/06/13 14:24:00-14:30:00 B2.4 10812010/06/13 15:45:00-15:59:00 B4.2 10812010/06/13 18:10:00-18:17:00 B1.8 1081

Events on 13 June 2010 - Movie

Temporal Analysis of M1.0 Flare

R1: summed average of SWAP 17.4 nm overAR1079 (also including AR1078 and AR1080)

R2: LYRA Aluminum: 17-80nm

R3: LYRA Zirconium: 1-20nm

R4: GOES long wavelength 0.1-0.8nm

R5: GOES short wavelength 0.05-0.4nm

Temporal Analysis of M1.0 Flare

Large Angle Rotation

Frequency Analysis of Flares using Wavelet

The continuous wavelet transform of a discrete sequence xn is defined as the

convolution of xn with a scaled and translated version of ψo(η):

By varying the wavelet scale s and translating along the localized time index n, one can construct a picture showing both the amplitude of any features versus the scale and how this amplitude varies in time.

€

Wn (s) = xnn ' =0

N −1

∑ Ψ* (n ' − n)δt

s

⎡

⎣ ⎢

⎤

⎦ ⎥

Several motherwavelets were analyzed and for no specific reasons, we selected the Morlet wavelet for our analysis.

Frequency Analysis of Flares using Wavelet

;; standard IDL parameters;; motherfunction: MORLET;; order,w0 6;; dscale: 0.1;; pad: no padding;; start_scale: 2*delta_t;; nscale: default value, but compute;;wv_args = {args, $

family: 'morlet', $order: 6, $ dscale: 0.1 , $ nscale: 0 , $ pad:0 , $ start_scale: 10 , $freq_scale: 1.02 $ from Torrence and Compo

}

wv_args.nscale = (ALOG2( ((size(*data))[1]) / wv_args.start_scale )) / wv_args.dscale + 1

The following frequencies are obtained: 9.8039 8.2440 6.9324 5.829 4.901 4.1220 3.4662 2.9147 2.450 2.0610 1.7331 1.4573 1.2254 1.0305 0.866 0.7286 0.61274 0.51525 0.43327 0.36434 0.30637 0.25762 0.2166 0.1821 0.1531 0.1288 0.10831 0.091085 0.076593 0.064406 0.054159 0.04554 0.038296 0.03220 0.02707 0.02277 0.019148 0.01610 0.013539 0.011385 0.009 0.008 0.0067 0.0056 0.0047 0.0040 0.0033 0.0028 0.0023 0.00201 0.00169

Frequency Analysis of Flares using Wavelet

Processing time is long. All the following plots have been based on 10 minutes intervals.

Scales on all following plots are all identical: xrange=10minutes

Uncertainty area not yet determined

Wavelet of M1.0 flare

Wavelet Training I: Two Frequencies

Linear scale

frequencies

0.1 Hz

0.014 Hz

Wavelet Training II: noise

Z-axis plotted in linear scale Z-axis plotted in log10 scale

Wavelet Training III: frequencies + noise

Frequency Analysis of M1.0 Flare using Wavelet Analysis

Plots in 10 minutes interval

05:10 – 05:20

05:20 – 05:30

05:30 – 05:40

05:40 – 05:50

All x-scales and y-scales and z-scales are identical over the plots.

05:10 – 05:20 05:20 – 05:30

05:30 – 05:40 05:40 – 05:50

05:10 – 05:20 05:20 – 05:30

05:30 – 05:40 05:40 – 05:50

0.002

0.003

0.007

0.014

0.028

0.054 Hz0.118

0.238

0.477

0.980

1.96

05:10 – 05:20 05:20 – 05:30

05:30 – 05:40 05:40 – 05:50

Conclusion

LYRA EUV channel time series (Zirconium, Aluminum) suitable for analysis of solar events

Frequency analysis

• No frequencies components/oscillations higher than 0.1/0.2 Hz found so far, but can not be excluded -> more analysis needed

• Oscillations found at 0.1 Hz and 0.014 Hz– No indication that these components could be caused by instrumental or spacecraft

effects

– Components detected for other flares, but are very seldom

– For the observed flare, there were 3 active regions near the limb, so it can not be excluded that the oscillations are caused by superposition of several events

– It’s likely however that the observed oscillations are caused by – Geometry: e.g. energy released in different directions and these are seen as oscillations

– Energy: e.g. physical processes at chromosphere

– Energy: e.g. energy loss during electron and ion evolution through corona

Next Steps

More systematic analysis

• Production of wavelet space as data product

• Processing using grid technology

• Further development of analysis tools

Combine with modeling efforts

Any comments, suggestions and discussions are welcome. I am happy to share results and software with you.