Phenomena | Parameter | Daily–several per year | Once per year | Once per 10 years | Once per 100 years | Once per 1000 years |
---|---|---|---|---|---|---|
Solar flare | X-ray peak flux | M1–X1 | X7.6 | X12 | X44 | X101 |
Energy [erg] |  < 2.0 × 1030 | 1.0 × 1031 | 1.0 × 1032 | 1.0 × 1033 | 1.0 × 1034 | |
Coronal mass ejection (CME) | Velocity [km/s] | 250–450 | 2000 | 3000 | 3800–4500 | 4700–6600 |
Kinetic energy [erg] |  |  |  | 4.4 × 1033 | 9.8 × 1033 | |
Solar energetic particles (SEPs) | Fluence (≥ 10 MeV) [1010 cm−2] at GEO |  |  ~ 0.1 |  ~ 1.0 |  ~ 2.4–5.1 |  ~ 3.8–14 |
EII [%・h] |  |  |  ~ 190 |  ~ 6600 |  ~ 223,000 | |
Solar radio burst [sfu] | Very high frequency (VHF, 30–300 MHz) |  |  |  |  < 2.8 × 109 |  |
Ultra-high frequency (UHF, 300–3000 MHz) |  |  |  |  < 1.2 × 107 |  | |
GPS (1176–1602 MHz) |  |  |  |  < 1.2 × 107 |  | |
F10.7 (2800 MHz) |  |  |  |  < 1.3 × 107 |  | |
Microwave (4000–20,000 MHz) |  |  |  |  < 3.7 × 107 |  | |
Variations of relativistic electron flux of the outer radiation belt | Electron fluence (> 2 MeV)[1010 cm−2sr−1] at GEO |  ~ 0.1 |  ~ 0.6 |  ~ 3.0 |  ~ 10 |  ~ 26 |
Magnetic storm | Dst index [nT] |  |  ~  − 220 |  ~  − 450 ± 30 |  ~  − 650 ± 110 |  ~  − 930 |
Substorm | AL index [nT] |  |  ~  − 3700 |  ~  − 4100 |  ~  − 4100 |  ~  − 4200 |
SML index [nT] |  − 460 |  − 3000 |  − 4000 |  − 5000 |  − 5900 | |
Total electron content (TEC) | @Tokyo [TECU] |  |  ≥ 90 |  ≥ 130 |  ≥ 190 |  |
@Kagoshima [TECU] |  |  ≥ 110 |  ≥ 160 |  ≥ 230 |  | |
@Hokkaido [TECU] |  |  ≥ 70 |  ≥ 105 |  ≥ 150 |  | |
Dellinger phenomenon | Absorption [dB] @6.6 MHz (long-circuit) |  |  ~ 71 |  ~ 83 |  ~ 93 |  ~ 100 |
Event duration [h] |  | 0.6–1.3 | 1.8–3.6 | 4.0–6.8 | 7.4–11.9 | |
Sporadic E-layer | Frequency propagating 1,000 km [MHz] |  | 100 | 110 |  ≥ 130 |  |
Frequency propagating 2,000 km [MHz] |  | 130 |  ≥ 180 |  ≥ 180 |  | |
Duration for foEs > 13.3 MHz [h] |  |  ~ 3 |  ~ 5 |  |  | |
Duration for foEs > 18 MHz [h] |  |  ~ 1–2 |  ~ 3 |  |  | |
Plasma bubble | Event duration [h] |  | 4–5 | 6 |  |  |
Polar cap absorption (PCA) | Invariant latitude, day @6.6 MHz 10 dB | 65° | 57° | 53° | 51° | 50° |
Invariant latitude, night @6.6 MHz 10 dB | 65° | 60° | 56° | 53° | 53° | |
Minimum duration [h] | 22 | 46 | 71 | 83 | 89 |