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Solar radio observations in Belgium

Solar radio observations in Belgium. C. Marqué, F. Clette , J.-L. Dufond , A. Ergen , J. Magdalenic , B. Dabrowski Royal Observatory of Belgium 2 nd LOFAR Solar KSP Workshop, Postdam June 24-25, 2009. Outlines. Historical overview Presentation of the solar radio projects

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Solar radio observations in Belgium

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  1. Solar radio observations in Belgium C. Marqué, F. Clette, J.-L. Dufond, A. Ergen, J. Magdalenic, B. Dabrowski Royal Observatory of Belgium 2nd LOFAR Solar KSP Workshop, Postdam June 24-25, 2009

  2. Outlines • Historical overview • Presentation of the solar radio projects • The CALLISTO spectrograph • Synergies between LOFAR & solar physics @ ROB • Scientific activities • Conclusion

  3. Historical overview • Location: Humain (Marche-en-Famenne), 100km SE of Brussels • Operated by ROB since 1954 • 1956: Routine radio flux observations at 169 & 610 MHz. • 1958-1972: Construction of the 408 MHz radioheliograph (48-antenna interferometer): operated only in slow-drift mode. • Lack of manpower and excessive maintenance workload: decommissioning of the interferometer (Sept. 2002) and of the 610 MHz radiometer (Aug. 2004)

  4. The Humain station

  5. A new development context: the STCE • STCE: Solar-Terrestrial Center of Excellence • Cross-disciplinary multi-institute structure dedicated to Sun-Earth relation studies • Belgian government commitment to support and bring together Belgian experts in solar physics, geomagnetism and aeronomy. • Teams from 3 federal institutes: ROB, BISA (space areonomy), RMI (meteorology) • More information at http://www.stce.be Solar activity monitoring from ground-based instruments (optical, radio) is one of the ROB WPs

  6. The Humain redeployment plan • Primary goals: monitoring of solar activity and research: solar flares, CMEs & irradiance. • Refurbishment of available hardware (now in progress): • Selection of a couple of antenna, new control system • New receivers • 2 specific kinds of instruments: • Radiometers at selected dm and cm wavelengths (0.5-10 GHz) for irradiance studies and flare physics; primary freq. 2.8 GHz (F10.7 cm). (DRAO, Pentincton) • Spectrometers in the m/dm range (CALLISTO) and later in the cm domain for flare/CME related physics. • Direct connection with the SIDC Regional Warning Center for Europe (ROB, Brussels)

  7. What is CALLISTO? CALLISTO is a low-cost, sweep frequency radio receiver primarily designed for solar observations (sporadic solar outbursts), built and designed by C. Monstein from the ETHZ institute It’s a network of instruments located around the world for an extended solar monitoring and for RFI mitigation CALLISTO: http://helene.ethz.ch/instrument/callisto/callisto_nf.html CALLISTO solar data: http://pandora.ethz.ch:8080/frontend/

  8. CALLISTO • Made from consumer electronics hardware (Philips TV tuner) • PC-controlled hardware with RS232 connection • Software for automatic observations (frequency program, schedule…) • Fine frequency overview mode (whole frequency range scanned at 62.5 kHz), takes about a min.

  9. CALLISTO in Humain • Log-periodic antenna, with Sun tracking capabilities • Observing since May 2008 • 45-400 MHz (test phase) • Spectrum monitoring • 2ndCallisto to be installed for high freq. monitoring • Near real time: http://sidc.be/humain

  10. Belgian RFI situation Spectral overview, pointing at the Sun, (Ref: 50 Ohm)

  11. Short terms development in spectrography • Extension of the available spectrum between 20 MHz and 3 GHz for solar observation • RFI mitigitation (local source) • Data processing effort for automatic burst recognition (space weather forecasts @ ROB), cataloging • Development of an home-made spectrograph

  12. Belgian solar community & LOFAR • Triggering of “burst mode” for LOFAR could be made on spectrograph observations such as CALLISTO (local receiver or rely on available network) • An automatic burst detection could feed the solar observation mode • PROBA2 (SWAP & LYRA): EUV imager and radiometer. Launch November 2nd 2009 • STCE science could benefit (meteor…)

  13. Science activities: radio team • Small group: 4 scientists (2 full time), 2 technical staff ( +2 to be recruted) • Hardware development (spectro and radiometers): just started • A primary science target: flare and CMEs • Density modeling: necessary for data analysis in EUV, radio • Two efforts: one with J. Magdalenic (fully radio) • One with B. Dabrowski: EUV forward modeling

  14. Science activities: flares, CMEs and shocks • Projects related to physics of flares and CMEs with JasminaMagdalenic - Zhukov: • Global waves and shocks: study of coronal parameters (density, temperature, Alfvén velocity distribution) • Belgian roposal for the propagation of shock waves from the corona to the Earth • Both rely on a joint study of spectrographic and imaging radio data (NançayRadioheliograph, LOFAR)

  15. Fundamental band Harmonic band 411 MHz, 14:22:34 UT Estimation of the coronal electron density Theevolution of thedominant NRH source is compared with the type II features in dynamic spectrum. Position of the NRH radio source →converted toradial heights →frequency (radial heights)

  16. observations show coronal electron density between 5x Saito(Saito et al., 1970) what is close to 2x Newkirk (Newkirk et al., 1966), and 2x Saito. • steep decrease of coronal density → consequence of possible projection effects? • f~ 216 MHz, 5x Saito → density ~ 5 · 108 cm-3 • f ~76 MHz, 2x Saito → density ~ 6 · 107 cm-3

  17. Conclusion • Revival of solar radioastronomy in Belgium (still modest) • Solar spectrography and irradiance • Numerous links with imaging instruments like Nançay and LOFAR: for solar activity monitoring and “pure” science purpose

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