21st european cosmic ray symposium kosice september 11th 2008 catia grimani and michele fabi urbino...
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21st European Cosmic Ray Symposium Kosice September 11th 2008
Catia Grimani and Michele Fabi
Urbino University and INFN Florence
The potentialities of LISA as an observatory for solar and cosmic-ray physics at 1 AU far from Earth
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21st European Cosmic Ray Symposium Kosice September 11th 2008
Summary
LISA-PF & LISA missions & orbits Radiation monitors on LISA-PF Solar and Cosmic-ray Physics on board LISA Conclusions
21st European Cosmic Ray Symposium Kosice September 11th 2008
LISA & LISA-PF LISA Michelson Interferometer in space for
gravitational wave detection down to 0.01 mHz:
3 S/C located at 5x106 km from each other near the ecliptic plane; 50x106 km behind the Earth Optical telescopes and inertial sensors Acceleration limit requirement: 3x10-15
m s -2 Hz-1/2
Launch expected in 2018- Duration 2-10 years
LISA-PF Demonstration mission for
LISA: two test masses placed at a distance of 30 cm
L1 orbit One order of magnitude below
the LISA requirements Launch expected in 2011
Km
21st European Cosmic Ray Symposium Kosice September 11th 2008
LISA SCIENTIFIC GOALS
21st European Cosmic Ray Symposium Kosice September 11th 2008
LISA-PF ORBIT
21st European Cosmic Ray Symposium Kosice September 11th 2008
LISA IN SPACE
21st European Cosmic Ray Symposium Kosice September 11th 2008
LISA orbit 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
21st European Cosmic Ray Symposium Kosice September 11th 2008
LISA Inertial sensor and test mass
VACT1
VACT2
VM
Csens1
Csens2
VAC
100 kHzL
L
Cp
Cp
21st European Cosmic Ray Symposium Kosice September 11th 2008
Radiation monitors (RM) will be placed on board the LISA spacecraft
RM design has been finalized for the PF only
21st European Cosmic Ray Symposium Kosice September 11th 2008
SKETCH OF PARTICLE DETECTOR FOR LISA-PF
1.4 cm
1.05
cm 2 cm
2 layers of silicon detectors Dimensions: 1.05 x 1.4 cm2
Thickness: 300 mLobo, 2004
Geometrical factor: One layer - 9.24 cm2 sr Coincidence - 0.87 cm2 sr
Copper box 6.4 mm thick
21st European Cosmic Ray Symposium Kosice September 11th 2008
Detector Positioning on LISA-PF
Ecliptic
Sun
EarthSpacecraft
Solar Panels
Spacecraft
to Sunto Earth
Radiation Monitor front plane
21st European Cosmic Ray Symposium Kosice September 11th 2008
Present RM characteristics
Galactic proton and helium nuclei (no 3He and 4He separation) in the whole energy range monitoring
SEPs above 70 MeV/n (p, He) monitoring Overall countrate on each silicon detector Ionization energy losses in the rear detector for
coincidence events only (50 keV-5 MeV) Maximum fluence 108 particles/cm2
21st European Cosmic Ray Symposium Kosice September 11th 2008
Galactic cosmic-ray variations and fluctuations Long-term variations 11-year variation (Sun Spots) 22-year opposite Global Solar Magnetic Field (GSMF) Polarity change Quasi-biennial variations
Short-term fluctuations Forbush decreases 27-day variation Minutes - hours (Observed by two different experiments at the same time: HIST on
POLAR and on INTEGRAL) see http://astro.ic.ac.uk/pwass/thesis/pjwThesis2 Shaul et al., 2006
21st European Cosmic Ray Symposium Kosice September 11th 2008
Solar Modulation and
Global Solar Magnetic Field Polarity
Alanko-Huotari, Mursala, Usoskin and Kovaltsov, Solar Physics, 238, 391, 2006
21st European Cosmic Ray Symposium Kosice September 11th 2008
Cosmic-ray proton observations during the last two solar cycles
CG et al. 30th ICRC 2007 Merida Mexico
21st European Cosmic Ray Symposium Kosice September 11th 2008
Solar Modulation of Galactic Cosmic Rays
Gleeson and Axford, Ap. J., 154, 1011, 1968
J(r,E,t) J(∞,E+)=
E2-Eo2 (E2-Eo
2
J: particle flux
r: distance from Sun
E: particle total energy
t: time
Eo= particle mass
= particle energy loss from infinity (different for each species)
Ok for positive polarity epoch data only!
21st European Cosmic Ray Symposium Kosice September 11th 2008
Reduction factors
Solar minimum - negative polarityR1=1+(0.4/1.602)*logE+(0.4/1.602)-0.4 0.1<E<4.0 GeV(/n)
High solar activity - negative polarityR2=0.61+1.41*E-1.2*E1.32+0.146*E1.95 0.1<E<1.6 GeV(/n)
21st European Cosmic Ray Symposium Kosice September 11th 2008
Solar polarity effect on GCR p, He, e- and e+
p
He
Boella G. et al., J. Geophys. Res. 106:355 2001
CG et al. 30th ICRC 2007 Merida MexicoCG, A&A, 474, 339, 2007
21st European Cosmic Ray Symposium Kosice September 11th 2008
Solar modulation during the next two solar cycles
D. Hathaway and Dikpati M. http://science.nasa.gov/headlines/y2006/10may_lagrange.htm
21st European Cosmic Ray Symposium Kosice September 11th 2008
Positive polarity cosmic-ray flux parameterization
F[E(GeV)]=A(E+B)-EParticles/(m2 sr s GeV)
A B
P (BESS97)
He(BESS97)
18000
850
1.09
0.915
3.66
3.17
0.87
0.42
P (BESS00)
He(BESS00)
18000
850
1.71
1.25
4.20
3.60
1.41
0.85
P(MASS89) 18000 1.57 3.95 1.16
P(BESS02) 18000 1.60 3.99 1.20
(Papini, CG & Stephens, Il nuovo Cimento, 19, 367, 1996; CG et al., CQG,21,S629, 2004)
21st European Cosmic Ray Symposium Kosice September 11th 2008
GCR p and He fluxes at the time of the LISA missions
CG et al., XXX International Cosmic-Ray Conference, Merida, Mexico July 2007CG et al., 7th Amaldi Conference Sidney Australia July 2007 presented by D. TombolatoCG and M. Fabi, Ionizing Radiation Detection and Data Exploitation Workshop, ESA/ESTEC, October 2007
21st European Cosmic Ray Symposium Kosice September 11th 2008
Part. A B Reduction Factor
LISA-PF
Positive
Polarity
p
He
18000
850
1.6
1.15
3.99
3.45
1.20
0.70
LISA-PF
Negative
Polarity
p
He
18000
850
1.6
1.15
3.99
3.45
1.20
0.70
R1(E)
0.1<E<1.6
GeV
LISA 2018 p
He
18000
850
1.09
0.915
3.66
3.17
0.87
0.42
LISA 2022 p
He
18000
850
1.27
0.99
3.66
3.17
0.87
0.42
R2(E)
0.1<E<4.0
GeV
Proton and Helium flux parameterization at the timeof the LISA missions
21st European Cosmic Ray Symposium Kosice September 11th 2008
Count rate and test-mass charging for the LISA missions (FLUKA Monte Carlo simulation)
Mission Part. Test-Mass
Charging
(%)
Part. Radiation
Monitor
Countrate
(%)
LISA-PF
Positive
Polarity
p
4He
3He
0.17
0.17
0.21
p+4He+3He 0.40
LISA-PF
Negative
Polarity
p
4He
3He
0.13
0.11
0.18
p+4He4+3He 0.38
LISA Sol. Min.
2018
Positive Polarity
p
4He
3He
1.0
1.0
1.0
p+4He+3He 1.0
LISA Sol. Max.
2022
Negative Polarity
p
4He
3He
0.53
0.50
0.51
p+4He+3He 0.65
For absolute rates see Araujo et al. Astr. Phys., 22, 451, 2005
21st European Cosmic Ray Symposium Kosice September 11th 2008
SOLAR FLARES (Reames, 1997)
Electron rich3He/4He =1Fe/O = 1H/He = 10QFe = 20Duration = hoursLongitude = 40-70Radio Type = III,V(II)X-rays = ImpulsiveEvents/year = about 1000
IMPULSIVEGRADUAL (CMEs)
Proton rich3He/4He =0.0005Fe/O = 0.1H/He = 100QFe = 14Duration = daysLongitude = more flat Radio Type = II,IVX-rays = GradualEvents/year = about 10
ONLY 1-2% of CMEs produce Solar Energetic Particles
21st European Cosmic Ray Symposium Kosice September 11th 2008
ESTIMATE OF NUMBER OF YEARLY SEP EVENTS DURING THE NEXT DECADE
Various methods are available in literature: Nymmik, 1999
We have estimated the yearly SEP-event number in the fluence range 106-1011 protons/cm2
above 30 MeV considering high and low solar cycle projections.
Nymmik has found a correlation between the yearly number of SEP events and the number of yearly predicted solar spot number:
NSEPs [NSSmin,NSSmax]=0.0694 NSS[min,max]
Nymmik has found that the number of SEP events show a power-law trend as a function of fluence
dNSEPs=C e- d
Where =4x109
and C was determind on the basis of the total number of expected SEP events
21st European Cosmic Ray Symposium Kosice September 11th 2008
Number of yearly expected solar spots during the next solar cycles
Year Minimum SS #
Maximum SS #
2009 9 39
2010 36 127
2011 57 220
2012 68 195
2013 67 149
2014 54 122
2015 44 88
2016 24 63
2017 11 16
2018 5 15
Solar Cycle 24
Year Average SS #
2019 4
2020 17
2021 37
2022 56
2023 63
2024 60
2025 50
2026 37
2027 23
2028 11
2029 5
Solar Cycle 25
21st European Cosmic Ray Symposium Kosice September 11th 2008
During the LISA-PF mission (6 months) we expect 4.4 events in the fluence range 106-109 protons/cm2
21st European Cosmic Ray Symposium Kosice September 11th 2008
Minimum number of SEP events expected during the next decade
106 - 107 p/cm2
107 - 108 p/cm2
108 - 109 p/cm2
109 - 1010 p/cm2
1010 - 1011 p/cm2
21st European Cosmic Ray Symposium Kosice September 11th 2008
Maximum number of SEP events expected during the next decade
106 - 107 p/cm2
107 - 108 p/cm2
108 - 109 p/cm2
109 - 1010 p/cm2
1010 - 1011 p/cm2
21st European Cosmic Ray Symposium Kosice September 11th 2008
Average number of SEP events expected during the solar cycle 25
106 - 107 p/cm2
107 - 108 p/cm2
108 - 109 p/cm2
109 - 1010 p/cm2
1010 - 1011 p/cm2
21st European Cosmic Ray Symposium Kosice September 11th 2008
Storini et al., 2008
Gnevyshev gap in Sunspot Area
21st European Cosmic Ray Symposium Kosice September 11th 2008
Storini et al., 2008
Gnevyshev gap in SEP parameters
21st European Cosmic Ray Symposium Kosice September 11th 2008
Taking into account the Gnevishev Gap, the total number of expected SEP events might be reduced by 25% in the year(s) of the very solar maximum
21st European Cosmic Ray Symposium Kosice September 11th 2008
LONGITUDE DEPENDENCE OF SOLAR EVENTS•Large CME shocks might cause flat longitude profiles•In the western flank of the shock the event is more dynamic than the rest of the CME •For central and eastern SEP events invariance begins after shock passage
Figure from Reames, 2002
21st European Cosmic Ray Symposium Kosice September 11th 2008
RADIATION MONITOR EXPECTED PERFORMANCE
21st European Cosmic Ray Symposium Kosice September 11th 2008
We expect a SEP flux difference among the LISA satellites associated with the same event ranging between 5 and 10%.This estimate was carried out on the basis of observed, energetic, proton fluxes related to gradual events differing by a few degrees in solar longitude.Further investigation is needed in order to take into account the role of different boundary conditions for
each event.
SEP FLUX AT SMALL STEPS IN LONGITUDE ABOVE 100 MeV
21st European Cosmic Ray Symposium Kosice September 11th 2008
Central-eastern event
Western event
Expected count rate variation on each silicon wafer
21st European Cosmic Ray Symposium Kosice September 11th 2008
Flare September 29th 1989
Flare February 16th 1984
Flare May 7th 1978
Figures fromGrimani&VoccaPHOEBUS Proposal; 2004
SOLARENERGETICPARTICLES
21st European Cosmic Ray Symposium Kosice September 11th 2008
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
Flux5
Cou
nt r
ate
GPm:galactic protons at solar minimumGPM:galactic protons at solar maximumF1: Flare 7 May 1978F2: Flare 16 February 1984F3: Flare 29 September 1989
21st European Cosmic Ray Symposium Kosice September 11th 2008
Expected count rate on both silicon layers
0
50
100
150
200
250
300
350
GPm GPM F1 F2 F3
Flux1
Flux2
Flux3
Flux4
Flux5
Cou
nt r
ate
GPm:galactic protons at solar minimumGPM:galactic protons at solar maximumF1: Flare 7 May 1978F2: Flare 16 February 1984F3: Flare 29 September 1989
21st European Cosmic Ray Symposium Kosice September 11th 2008
GALACTIC AND SOLAR PARTICLE IONIZATION ENERGY LOSSES
IN PARTICLE MONITORS
21st European Cosmic Ray Symposium Kosice September 11th 2008
ROLE OF ELECTRONS ON BOARD LISA
21st European Cosmic Ray Symposium Kosice September 11th 2008
CG et al., in preparation
BEST-LINE FIT TO THE INTERPLANETARY ELECTRON SPECTRUM DURING A POSITIVE POLARITY PERIOD
Jovian maximum
Jovian minimum
21st European Cosmic Ray Symposium Kosice September 11th 2008
BEST-LINE FIT TO THE INTERPLANETARY ELECTRON SPECTRUM DURING A NEGATIVE POLARITY PERIOD
Jovian maximum
Jovian minimum
Solar electron fluxes
Flare September 7th 1973Flare November 3rd 1973
21st European Cosmic Ray Symposium Kosice September 11th 2008
SEP FORECAST
Posner (2007) has developed a method for SEP event forecasting.Electron fluxes of solar origin in the energy range between 0.3 and1.2 MeV reach 1 AU always BEFORE energetic protons in the energy range <50 MeV.
INTERPLANETARY ELECTRONS, INCLUDING SOLAR, ACCOUNT FOR 5% AND 13%, RESPECTIVELY, OF PROTONSAT SOLAR MINIMUM AND MAXIMUM RESPECTIVELYON THE RM COUNT RATE AND REDUCE 15% THE NET TEST-MASS CHARGING WHILE INCREASE OF 8%THE SHOT NOISE AT SOLAR MINIMUM, TWICE THIS VALUE AT SOLAR MAXIMUM … MORE THAN THIS…ELECTRONS ALLOW…
21st European Cosmic Ray Symposium Kosice September 11th 2008
(*) The intensity increase of both electrons and protons are correlated
(*) Both are correlated to the longitude between the observer and the flare
(*) Timescales of electron intensity increase are of tens of minutes.
(*) Protons above 100 MeV can be forecasted through the detection of 1 MeV electrons. Delay time of protons with respect to electrons range between 10 minutes and 1 hour.
21st European Cosmic Ray Symposium Kosice September 11th 2008
Time delay between solar electrons and protons
21st European Cosmic Ray Symposium Kosice September 11th 2008
Conclusions
Particle monitors on board LISA missions will provide precious clues on solar and cosmic-ray physics
LISA will allow us to map SEP fluxes above 100 MeV(/n) as a function of time at small steps in longitude.
An electron monitor for SEP forecasting would be recommended on LISA.
21st European Cosmic Ray Symposium Kosice September 11th 2008
ESA and Space Weather
One man’s noise is another man data III Space Weather Week Brussels -Belgium November 13th-17th 2006
Our proposition to use LISA RM for solar physics and space weather investigations is now officially part of the ESA program for future space weatherinvestigations.
From the talk by E. Daly (ESA space environment specialist,Head of Space Environment Effects Analysis Section):
21st European Cosmic Ray Symposium Kosice September 11th 2008
Thank you for your attention!
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