1. PHOEBUS* on LISA: A Proposal for Solar Physics on LISA INFN-SPAZIO/2 Riunione sulle prospettive della Fisica Astroparticellare nello spazio LNF, 16 Febbraio 2005 Catia Grimani 1 & Helios Vocca 2 (1) Urbino University and INFN Florence (2) University and INFN Perugia * PHysics Of Events BUrsted by the Sun

2. Helios Vocca & Catia Grimani - INFN-SPAZIO/2- LNF - 16 Febbraio 2005 THE PARTICLE COUNTERS ON BOARD LISA will allow to monitor the flux of particles with energies larger than 100 MeV. This energy cut-off has been set on the basis of the minimum energy of primary and solar cosmic rays able to penetrate the matter that surrounds the test-masses. Consequently, only galactic cosmic rays and the transit of CMEs will be detected on LISA, being the maximum energy of impulsive solar flare accelerated particles 50 MeV.

3. Helios Vocca & Catia Grimani - INFN-SPAZIO/2- LNF - 16 Febbraio 2005 SKETCH OF SILICON DETECTORS ON LISA PF 1.4 cm 1.05 cm 2 cm 2 layers of silicon detectors Dimensions: 1.05 x 1.4 cm 2 Thickness: 300  Lobo, 2004

4. Helios Vocca & Catia Grimani - INFN-SPAZIO/2- LNF - 16 Febbraio 2005 LISA spacecraft characteristics Distance from the Sun 0.9933 ÷ 1.0133 AU Latitude off the ecliptic 0.7 o ÷ 1.0 o Longitude difference with respect to Earth 19 o ÷ 21 o

5. Helios Vocca & Catia Grimani - INFN-SPAZIO/2- LNF - 16 Febbraio 2005 Particle counters devoted to test-mass charging monitoring can be used to map the transit of very energetic solar particle (SEP) fluxes correlated to CMEs through the experiment spacecraft. LISA OFFERS A GREAT OPPORTUNITY!!!!

6. Helios Vocca & Catia Grimani - INFN-SPAZIO/2- LNF - 16 Febbraio 2005 The study of Coronal Mass Ejection (CME) dynamics is mandatory for: Space Weather forecasting (Sezione di Perugia) Solar physics modelization (Sezione di Firenze - Urbino)

7. Helios Vocca & Catia Grimani - INFN-SPAZIO/2- LNF - 16 Febbraio 2005 CME propagation The high fluence active Sun period is of 7 years, from 2 years before the solar maximum year to 4 years after. The propagation time (between event and appearance of protons at the spacecraft) is a strong function of the longitude of the solar event. The time of the onset corresponds to the time at which the shock intercepts the magnetic field lines to the spacecraft Reames, D. V., 2002, Space Radiation (Japan), 3, 69 The shock nose of a typical gradual event takes about two days to reach Earth or LISA, might take a few hours to propagate between Lisa and Earth, and the order of one hour to pass through the three LISA detectors

8. Helios Vocca & Catia Grimani - INFN-SPAZIO/2- LNF - 16 Febbraio 2005 Space Weather can affect: Satellite Systems command and data modifications or satellite surface charging degrading their lifetime and affecting the electronics Communication Systems changes radio waves propagation characteristics and lead to depression in the maximum usable frequencies Power Systems transmission lines are potentially very good conductors of geomagnetic induced currents Navigation Systems accuracy of navigation systems depends on accurately knowing the altitude of the ionosphere’s lower boundary Human Exposure increased radiation exposure to astronauts and airplane crew and passengers on polar routes can be lethal

9. Helios Vocca & Catia Grimani - INFN-SPAZIO/2- LNF - 16 Febbraio 2005 PHOEBUS PHysics Of Events BUrsted by the Sun on LISA Fi/Ub Activity: SEP flux mapping Overall particle countrate Proton energy spectrum: 100-500 MeV Helium energy spectrum: 100-500 MeV/n Solar Iron energy spectrum: 200-700 MeV/n

10. Helios Vocca & Catia Grimani - INFN-SPAZIO/2- LNF - 16 Febbraio 2005 Flare September 29th 1989 Flare February 16th 1984 Flare May 7th 1978

11. Helios Vocca & Catia Grimani - INFN-SPAZIO/2- LNF - 16 Febbraio 2005 Expected count rate on one silicon layer Counting rate GPm:galactic protons at solar minimum GPM:galactic protons at solar maximum F1: Flare 7 May 1978 F2: Flare 16 February 1984 F3: Flare 29 September 1989

12. Helios Vocca & Catia Grimani - INFN-SPAZIO/2- LNF - 16 Febbraio 2005 Expected count rate on both silicon layers Counting rate GPm:galactic protons at solar minimum GPM:galactic protons at solar maximum F1: Flare 7 May 1978 F2: Flare 16 February 1984 F3: Flare 29 September 1989

13. Helios Vocca & Catia Grimani - INFN-SPAZIO/2- LNF - 16 Febbraio 2005 Central-eastern event Western event Expected countrate variation on one silicon wafer

14. Helios Vocca & Catia Grimani - INFN-SPAZIO/2- LNF - 16 Febbraio 2005 Protons solar minimum Protons solar maximum Protons solar flare Proton energy spectra in one silicon wafer

15. Helios Vocca & Catia Grimani - INFN-SPAZIO/2- LNF - 16 Febbraio 2005 Helium solar minimum Helium solar maximum Helium Flare Helium energy spectra in one silicon wafer

16. Helios Vocca & Catia Grimani - INFN-SPAZIO/2- LNF - 16 Febbraio 2005 Solar Iron energy spectrum in one silicon wafer (Q= =14)

17. Helios Vocca & Catia Grimani - INFN-SPAZIO/2- LNF - 16 Febbraio 2005 Acknowledgements Many thanks to: M. Candidi (IFSI/CNR Italy) M. Storini (IFSI/CNR Italy) E. Daly (ESA) M. Busso (INAF/University of Perugia) E. Antonucci (INAF/Observatory of Turin) B. Sanahuja (University of Barcelona) A. A.Aran (University of Barcelona) M. Panasyuk (University of Moscow) R. A. Nymmik (University of Moscow) V. N. Mileev (University of Moscow) for very useful discussions and suggestions regarding this project