Variability of Trapped and Transient
Radiation Environment on Highly Elliptical
high inclination (Molniya) orbit
L. Trichtchenko and L. Nikitina
OUTLINE
• MOTIVATION OF STUDY
• MOLNIYA ORBIT
• DATA AVAILABILITY
• EVENT JULY 2000
• VARIATIONS IN THREE ZONES
•ANNUAL VARIABIITY
•
CONCLUDING REMARKS
MOTIVATION
Canadian Polar Communications and Weather (PCW) mission
planned to put two satellites in an elliptical orbit over the North
Pole to provide reliable and continuous 24/7 communication
services and to monitor weather and climate changes in the entire
Arctic region.
Need: study of the satellite environment at planned orbit
The first orbit of choice : Molniya,
Other candidate orbits: 16 hrs TAP, 24 hrs. Tundra
Current status-Phase A completed, in search for different options
(business case, PPP, etc).
ESA has expressed interest in Molniya orbit as well…
MOLNIYA ORBIT
PCW Molniya orbit sample:
Apogee:39819.04 km
Perigee:530.96 km
Inclination:63.44°
R. A. A. N.:252.80°
Argument of Perigee:270.00°
True Anomaly:0.00°
Period:11.96 hrs
MOLNIYA ORBIT: Space Weather Studies
Uniqueness of orbit for particle dynamics:
trapped (rad belts) and transient (outer magnetosphere) radiation,
Horns and equatorial regions.
Uniqueness of orbit for magnetic filed measurements:
Polar and cusp, high and low altitudes (has never being done)
Electrons>1MeV
Protons>1MeV
~ Molniya orbit
DATA AVAILABILITY
Rad/min
30
3
0.3
0.03
0.003
Data: HEO-3 US AirForce, Paul O’Brian and collaborators: http://www.virbo.org
electrons, protons, dose rate, R, time along orbit, L,B (model), MLT
no orbit details
DATA AVAILABILITY
Total dose;
Protons P4-P7: >5 MeV, 8.5-35 MeV, 16-40 MeV, 27-45 MeV
Electrons E3-E6: >0.45 MeV, >0.63 MeV, >1.5 MeV, >3MeV
Total dose rate
behind 5 Mils Al
long duration SEP
at high latitude/high altitude
Short “spikes”- fast radiation
belts passage
2000
EVENT JULY 2000
EVENT JULY 2000
10 July 2000
11 July 2000
12 July 2000
13 July 2000
14 July 2000
15 July 2000
16 July 2000
17 July 2000
18 July 2000
19 July 2000
20 July 2000
21 July 2000
22 July 2000
23 July 2000
24 July 2000
25 July 2000
VARIABILITY (PROTONS)
2000, Protons16-40 MeV
2
1
Trapped
SEP-Associated
VARIABILITY (PROTONS)
Annual variations of maximum flux for p+~16-40 MeV
1
2
VARIABILITY (ELECTRONS)
2000, Electrons>0.63 MeV
1
2
3
VARIABILITY
Annual variations of maximum flux location for e->0.63 MeV
2
FAST
1
SLOW
VARIABILITY (ELECTRONS)
2000, Electrons>0.63 MeV, 2.5<R<5 and R<2.5
ANNUAL VARIABILITY
Rad/min
30
3
0.3
0.03
0.003
ANNUAL VARIABILITY
Rad/min
30
3
0.3
0.03
0.003
ANNUAL VARIABILITY
Rad/min
30
3
0.3
0.03
0.003
ANNUAL VARIABILITY
Rad/min
30
3
0.3
0.03
0.003
CONCLUSIONS
• MOLNIYA ORBIT IS ATTRACTIVE ORBIT FOR OPERATIONAL
MISSIONS AND FOR SPACE ENVIRONMENT STUDIES
•
PARTICLE POPULATION IS HIGHLY DYNAMICAL
• STRONG INFLUENCE OF SEP EVENTS DUE TO LONG
DWELLNG TIME IN HIGH ALTITUDE/HIGH ALTITUDE REGION
• TRAPPED POPULATION DEMONSTRATES TWO
COMPONENTS, SLOW (STABLE) AND FAST VARYING (SOLAR
WIND EFFECTS)
• more studies will follow…
THANKS TO DATA PROVIDERS!