Manual

radio bursts or SID observed or expected.
Moderate: Eruptive regions on the solar disk; fewer than five
class M x-ray events with centimetric radio bursts and SID
observed or expected.
High: Active regions on the solar disk; several class M x-ray
events with centimetric radio bursts and strong SID; and/or one
or two importance 2 chromospheric flares or class X x-ray
events observed or expected.
Very high: Region capable of producing protons on the sun;
one or more chromospheric flares of importance 2 or greater
with outstanding centimetric radio bursts (500 flux units or
greater), class x-ray bursts and major SID observed or
expected.
X-ray events:
Class C-any solar x-ray burst with a peak flux of 1-8 Å of
less than 10
-5
Watts M
-2
Class M-a solar x-ray burst with a peak flux at 1-8 Å greater
than or equal to 10
-5
but less than 10
-4
Watts M
-2
Class X-a solar x-ray burst with a peak flux at 1-8 Å greater
than or equal to 10
-4
Watts M
-2
B.2. Geomagnetic Field:
Quiet: A-Index ≤7; usually no K-indices >2
Unsettled: 7 < A-Index < 15; usually no K-indices > 3
Active: 15 ≤ A-Index < 30; a few K-indices of 4
B.3. Geomagnetic Storm:
Minor: 30 ≤ A-Index < 50; K-indices mostly 4 and 5
Major: A-Index ≥ 50; solar K-indices of 6 or greater
B.4. Major Solar Flare: A flare of optical importance ≥ 2B with a
centimetric radio burst of 500 flux units or more; or an X x-ray
event of duration ≥ 180 min. regardless of optical flare
importance.
B.5. Proton Flare: Protons by satellite detectors (or polar cap
absorption by riometer) have been observed in time
association with a chromospheric flare.
Appendices
13-3
KHF 950/990 Pilots Guide
Rev. 0
Dec/96