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Observational evidences of the propagating waves in/above chromospheric network

Observational evidences of the propagating waves in/above chromospheric network. Peter Gömöry Astronomical Institue of the Slovak Academy of Sciences. Institut d’Astrophysique Spatiale, Orsay, France. Motivation (I).

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Observational evidences of the propagating waves in/above chromospheric network

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  1. Observational evidences of the propagating waves in/above chromospheric network Peter Gömöry Astronomical Institue of the Slovak Academy of Sciences Institut d’Astrophysique Spatiale, Orsay, France

  2. Motivation (I) • previous work based on analysis of the SOHO/CDS measurements(Gömöry et al. 2006, A&A 448, 1169) • target: chromospheric network near the center of the solar disk • spectral lines: He I 584.33 Å (log T = 4.5) → chromosphere O V 629.73 Å (log T = 5.3) → transition region Mg IX 368.07 Å (log T = 6.0) → corona • analyzed parameters: temporal variations of the I and vD • techniques: cross-correlations, wavelet and phase difference analysis • determined results • significant negative time shift of ~27 s between temporal variations of the He I and O V intensities • determined time shift dominated by oscillations with ~300 s periodicity • no relevant time shift between temporal variations of the He I and O V Doppler shifts • only very ambiguous results based on the analysis of the temporal variations of the Mg IX intensities and Doppler shifts Institut d’Astrophysique Spatiale, Orsay, France

  3. Motivation (II) • interpretation of the results • negative time shift between the He I and O V intensities and no time shift between their Doppler shifts → non-radiative energy had to be transferred from transition region to chromosphere without any significant bulk mass motion  downward propagating magneto-acoustic waves in network • ambiguous interpretation of the results based on the Mg IX intensities and Doppler shifts  problems with the wave source localization (transition region or corona?) • possible explanations • observed parts of the transition region and corona not magnetically coupled • presence of waves only in the low-lying loops • verification of our results • longer dataset • better coverage of the solar atmosphere  more spectral lines • better signal in spectral lines with the formation temperature higher than 106 K  HINODE instruments Institut d’Astrophysique Spatiale, Orsay, France

  4. Motivation (II) • interpretation of the results • negative time shift between the He I and O V intensities and no time shift between their Doppler shifts → non-radiative energy had to be transferred from transition region to chromosphere without any significant bulk mass motion  downward propagating magneto-acoustic waves in network • ambiguous interpretation of the results based on the Mg IX intensities and Doppler shifts  problems with the wave source localization (transition region or corona?) • possible explanations • observed parts of the transition region and corona not magnetically coupled • presence of waves only in the low-lying loops • verification of our results • longer dataset • better coverage of the solar atmosphere  more spectral lines • better signal in spectral lines with the formation temperature higher than 106 K  HINODE instruments Institut d’Astrophysique Spatiale, Orsay, France

  5. Motivation (II) • interpretation of the results • negative time shift between the He I and O V intensities and no time shift between their Doppler shifts → non-radiative energy had to be transferred from transition region to chromosphere without any significant bulk mass motion  downward propagating magneto-acoustic waves in network • ambiguous interpretation of the results based on the Mg IX intensities and Doppler shifts  problems with the wave source localization (transition region or corona?) • possible explanations • observed parts of the transition region and corona not magnetically coupled • presence of waves only in the low-lying loops • verification of our results • longer dataset • better coverage of the solar atmosphere  more spectral lines • better signal in spectral lines with the formation temperature higher than 106 K  HINODE instruments Institut d’Astrophysique Spatiale, Orsay, France

  6. HINODE data (I) • HINODE/EIS → spectroscopic measurements of the TR and corona • target: chromospheric network near the center of the solar disk • date/time: August 18, 2007; 10:49 UT – 13:20 UT • 11 spectral lines: • He II 256 Å (log T = 4.9); Fe VIII 185 Å (log T = 5.6); Si VII 275 Å (log T = 4.9) → transition region • Fe X 184 Å (log T = 6.0); Fe XII 195 Å (log T = 6.1); Fe XIII 196 Å (log T = 6.2); Fe XIII 202 Å (log T = 6.2); Fe XIII 203 Å (log T = 6.2); Fe XV 284 Å (log T = 6.3); Ca XVII 192 Å (log T = 6.7); Fe XXIV 192 Å (log T = 7.2) → corona • observing modes: • 2D rasters → spatial coalignment with other data (DOT,TRACE, SoHO/EIT,CDS) • number of repetitions: 6 (3 before and 3 after “sit-and_stare” mode) • slit: 2” × 304” • step in X direction: 2”; number of steps: 41”  FOV: 82” × 304” • 1D “sit-and-stare” → temporal evolutions of the I and vD in/above network • number of repetitions: 5 • exposure time: 10 s + readout; number of exposures per one run: 135 • duration of one run: ~25 min.  total duration: ~ 125 min. (~2 hours) • slit: 2” × 304” Institut d’Astrophysique Spatiale, Orsay, France

  7. HINODE data (II) He II 256 Å (log T = 4.9) Y = 304” Fe XII 195 Å (log T = 6.1) Y = 304” Ca XVII 192 Å (log T = 6.7) Y = 304” Fe XXIV 192 Å (log T = 7.2) Y = 304” X = 82” t ~ 25 min t ~ 125 min Institut d’Astrophysique Spatiale, Orsay, France

  8. HINODE data (III) • HINODE/SOT → context images of the photosphere and chromosphere • instrument: broad-band filter imager • date: August 18, 2007 • time: 10:32 UT – 13:29 UT • pointing: FOV centered around the EIS slit position • spectral channels: G-band and Ca II H • cadence of images: 10 s per filtergram • number of exposures per channel: 304 • FOV: 109” × 109” Y = 109” G-band Y = 109” Ca II H X = 109” Institut d’Astrophysique Spatiale, Orsay, France

  9. Planned analysis • similar to our previous work (i.e. cross-correlations, wavelet analysis, phase difference analysis) but applied on much more complex dataset taken on August 18, 2007 • dataset • HINODE/EIS: spectroscopy → searching for the evidences of propagating waves in the transition region and corona • HINODE/SOT: imaging → photospheric and chromospheric response to propagating waves; dynamics of bright points → possible source of waves • SoHO/CDS: spectroscopy → presence of possible waves in the upper chromosphere and transition region • SoHO/MDI: magnetometry → changes in the photospheric magnetic field → physical mechanism responsible for the excitation of waves • SoHO/EIT: imaging → context images of the chromosphere and corona • TRACE: imaging → context images of the corona • DOT: imaging → photospheric and chromospheric response to propagating waves; Hα channel with high spatial resolution Institut d’Astrophysique Spatiale, Orsay, France

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