The Sun is entering its minimum activity phase. In the past week, there was only one active region (NOAA 2699) observed on the solar disk and produces 4 C-class flares with maximum C8.1 on February 7th. Also, several types III solar radio burst were detected, while no noteworthy CMEs happened in the past week. Solar activity next week is predicted to be quiet because there is no new eruptive region expected to emerge within the next couple days.
Geomagnet conditions on February, 2nd – February, 8th 2018 was in quiet conditon. Local response from Kupang observatory seen from K index with maximum value was 3. Minimum Dst index was -7 nT on 2 February 2018 and maximum Kp index was 2. Small substorm has occurred several times during the week with the Ae index showing the value of ≤ 1000 nT and duration range around 2-3 hours. The largest substorm occurred on 5 February 2018 with intensity ≤ 1000 nT for 7 hours. The electron flux were on the low level around 10 [/cm2/sec/sr].
Ionosphere conditions in this week were in quiet to strong level. The depression of foF2 lower than 30% from its median values occurred for 2.25 hours at noon and postmidnight on February 7th. The foF2 depressions were impacting the radiowave propagation over the ionosphere which known as the MUF Depression. Beside that, the minimum frequencies (fmin) of the ionosphere in this week were in quiet conditions. The increment of fmin could be a source of disturbance in the HF radio communication which known as Shortwave Fadeout (SWF) or Radio Blackout (RB). Based on the ionospheric observations using GISTM over Bandung, the scintillation (S4) condition for this week was in moderate level with S4 index value between 0.25 and 0.50 on February 4th-6th. The error positioning conditions were in normal condition that determined by the index W values of ± 1.
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