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

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

Outline

INTRODUCTION TO PROBA2INTRODUCTION TO LYRATEMPORAL ANALYSIS OF CX FLARE ON 2010-06-15TFREQUENCY ANALYSIS OF SAME FLAREINTRODUCTION TO WAVELETWAVELET ANALYSIS OF LYRA DATAFLARE RESULTSCONCLUSION 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 PROBALYRA 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 nutshellTechnology Demonstrators17 technological demonstrators: BepiColombo star tracker (Galileo Avionica), Digital Sun Sensor (TNO), GPS Receiver (Alcatel, DLR), Laser Reflector (ESTEC), Built as part of ESAs 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 LYRASWAPFlexible 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 1-20nmUnit 2 is operated continuously at 20 Hz (100Hz demonstrated), Unit1 and Unit3 for calibration purpose and dedicated campaigns

Spectral Response of LYRA EUV ChannelsMeasured spectral transmittance of the Al (157.9 nm thick) and the Zr (141.3 nm thick) filters from Luxel corp. between 1 and 30 nmMeasured spectral transmittance of the Acton Research corp. filters: Lyman- filters (N122, XN122) and 210-B Herzberg filter between 110 nm and 2600 nmFrom 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 2010Several 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 2010Several 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 FlareR1: 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 FlareLarge Angle Rotation

Frequency Analysis of Flares using WaveletThe continuous wavelet transform of a discrete sequence xn is defined as the convolution of xn with a scaled and translated version of o():

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.

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=10minutesUncertainty area not yet determined

Wavelet of M1.0 flare

Wavelet Training I: Two FrequenciesLinear scalefrequencies0.1 Hz0.014 Hz

Wavelet Training II: noiseZ-axis plotted in linear scaleZ-axis plotted in log10 scale

Wavelet Training III: frequencies + noise

Frequency Analysis of M1.0 Flare using Wavelet Analysis

Plots in 10 minutes interval05:10 05:2005:20 05:3005:30 05:4005:40 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 05:500.002

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

ConclusionLYRA EUV channel time series (Zirconium, Aluminum) suitable for analysis of solar eventsFrequency analysisNo frequencies components/oscillations higher than 0.1/0.2 Hz found so far, but can not be excluded -> more analysis neededOscillations found at 0.1 Hz and 0.014 HzNo indication that these components could be caused by instrumental or spacecraft effectsComponents detected for other flares, but are very seldomFor 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 eventsIts likely however that the observed oscillations are caused by Geometry: e.g. energy released in different directions and these are seen as oscillationsEnergy: e.g. physical processes at chromosphereEnergy: e.g. energy loss during electron and ion evolution through corona

Next StepsMore systematic analysisProduction of wavelet space as data product Processing using grid technologyFurther development of analysis toolsCombine with modeling effortsAny comments, suggestions and discussions are welcome. I am happy to share results and software with you.