2.2 Lunar Radiation Environment
23
Table 2.1 Basic characteristics of solar particle events
Proportion of particles Energy
Integral flux of particles
higher than
10 MeV/cm −2
Peak of differential flux
of particles higher than
10 MeV/(cm −2 ·s-1)
96.4% of proton, 3.5%
of α particle and about
0.1% of other heavy
nucleus particle
As high as GeV As much as 10 10
As much as 10 5
Number of Solar Proton Events
Number of Macula Each Month
Total Amount of Injection in Events/ (cm -2
)
Year
Higher Than 10MeV
Higher Than 30MeV
Fig. 2.1 Relationship between the integral flux of proton and the average value macula over months
in the solar proton events during the No. 19~23 solar activity week
of heavy nuclei particles is low, its effect shall not be ignored. In fact, just like the
proton and α particle, the heavy nuclei particles are an important source of single
event effect on spacecraft.
The observation records to date show that the solar particle event can be classified
as impulsive event and progressive event. The impulsive event is generally caused by
solar flare eruption and is rich in electrons of energy ranging from 1 keV to 100 keV.
The ratio of
3 He to
4 He is relatively high. But the duration of the event is short
(usually several hours) and the integral flux of high-energy flux is generally low.
The progressive solar particle event is primarily caused by coronal mass ejection and
its primary component is proton. Such events usually last longer (several days) and
the integral flux of high-energy particles may exceed 10
9 cm
−2 . Therefore, the more
intense solar particle event is generally the progressive event.
The solar particle event has a strong correlation with the intensity of solar activity.
Figure 2.1 shows the relationship between the integral flux of proton and the average
23
Table 2.1 Basic characteristics of solar particle events
Proportion of particles Energy
Integral flux of particles
higher than
10 MeV/cm −2
Peak of differential flux
of particles higher than
10 MeV/(cm −2 ·s-1)
96.4% of proton, 3.5%
of α particle and about
0.1% of other heavy
nucleus particle
As high as GeV As much as 10 10
As much as 10 5
Number of Solar Proton Events
Number of Macula Each Month
Total Amount of Injection in Events/ (cm -2
)
Year
Higher Than 10MeV
Higher Than 30MeV
Fig. 2.1 Relationship between the integral flux of proton and the average value macula over months
in the solar proton events during the No. 19~23 solar activity week
of heavy nuclei particles is low, its effect shall not be ignored. In fact, just like the
proton and α particle, the heavy nuclei particles are an important source of single
event effect on spacecraft.
The observation records to date show that the solar particle event can be classified
as impulsive event and progressive event. The impulsive event is generally caused by
solar flare eruption and is rich in electrons of energy ranging from 1 keV to 100 keV.
The ratio of
3 He to
4 He is relatively high. But the duration of the event is short
(usually several hours) and the integral flux of high-energy flux is generally low.
The progressive solar particle event is primarily caused by coronal mass ejection and
its primary component is proton. Such events usually last longer (several days) and
the integral flux of high-energy particles may exceed 10
9 cm
−2 . Therefore, the more
intense solar particle event is generally the progressive event.
The solar particle event has a strong correlation with the intensity of solar activity.
Figure 2.1 shows the relationship between the integral flux of proton and the average