PHOEBUS* on LISA: A Proposal for Solar Physics on LISA INFN-SPAZIO/2 Riunione sulle prospettive...

PHOEBUS* on LISA:PHOEBUS* on LISA:A Proposal for Solar Physics on LISAA Proposal for Solar Physics on LISA

INFN-SPAZIO/2Riunione sulle prospettive della Fisica Astroparticellare nello spazio

LNF, 16 Febbraio 2005

Catia Grimani1 & Helios Vocca2

(1) Urbino University and INFN Florence (2) University and INFN Perugia

* PHysics Of Events BUrsted by the Sun* PHysics Of Events BUrsted by the Sun

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.


SKETCH OF SILICON DETECTORS ON SKETCH OF SILICON DETECTORS ON LISA PFLISA PF

1.4 cm

1.05

cm

2 cm

2 layers of silicon detectors Dimensions: 1.05 x 1.4 cm2

Thickness: 300

Lobo, 2004


LISA spacecraft characteristicsLISA spacecraft characteristics

• Distance from the Sun

0.9933 ÷ 1.0133 AU

• Latitude off the ecliptic

0.7o ÷ 1.0o

• Longitude difference with respect to Earth

19o ÷ 21o


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!!!!LISA OFFERS A GREAT OPPORTUNITY!!!!


The study of Coronal Mass Ejection (CME) dynamics is mandatory for:

• Space Weather forecasting(Sezione di Perugia)

• Solar physics modelization(Sezione di Firenze - Urbino)


CME propagationCME propagationThe 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


Space Weather can affect:Space Weather can affect:

•Satellite Systemscommand and data modifications or satellite surface charging degrading their lifetime and affecting the electronics

•Communication Systemschanges radio waves propagation characteristics and lead to depression in the maximum usable frequencies

•Power Systemstransmission lines are potentially very good conductors of geomagnetic induced currents

•Navigation Systemsaccuracy of navigation systems depends on accurately knowing the altitude of the ionosphere’s lower boundary

•Human Exposureincreased radiation exposure to astronauts and airplane crew and passengers on polar routes can be lethal


PHOEBUSPHOEBUSPHysics Of Events BUrsted by the SunPHysics Of Events BUrsted by the Sun

on on LISALISAFi/Ub Activity: SEP flux mapping

Overall particle countrate

Proton energy spectrum: 100-500 MeVHelium energy spectrum: 100-500 MeV/nSolar Iron energy spectrum: 200-700 MeV/n


Flare September 29th 1989

Flare February 16th 1984

Flare May 7th 1978


Expected count rate on one silicon layer

0

500

1000

1500

2000

2500

3000

3500

4000

GPm GPM F1 F2 F3

Flux1

Flux2

Flux3

Flux4

Flux5Cou

ntin

g ra

te

GPm:galactic protons at solar minimumGPM:galactic protons at solar maximumF1: Flare 7 May 1978F2: Flare 16 February 1984F3: Flare 29 September 1989


Expected count rate on both silicon layers

0

50

100

150

200

250

300

350

GPm GPM F1 F2 F3

Flux1Flux2Flux3Flux4Flux5C

ount

ing

rate

GPm:galactic protons at solar minimumGPM:galactic protons at solar maximumF1: Flare 7 May 1978F2: Flare 16 February 1984 F3: Flare 29 September 1989


Central-eastern event

Western event

Expected countrate variation on one silicon wafer


Protons solar minimum

Protons solar maximum

Protons solar flare

Proton energy spectrain one silicon wafer


Helium solar minimum

Helium solar maximum

Helium Flare

Helium energy spectrain one silicon wafer


Solar Iron energy spectrumin one silicon wafer (Q=<Q>=14)


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. 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

PHOEBUS* on LISA: A Proposal for Solar Physics on LISA INFN-SPAZIO/2 Riunione sulle prospettive...

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