The Sun condition has been very quiet for the past weeks as it has entered a minimum activity phase. Event record last week explained that there was no flare, radio burst, CME, as well as filament eruption on the Sun. NOAA 2704 and 2705 are two active regions observed last week. Active region 2706 which emerge on 20 April is the only one active region on the disk for the next week. No flare is predicted to erupt from this region such that solar activity is forecasted to be quiet.
Geomagnetic conditions on April, 13th – 16th 2018 was in quiet. Minimum Dst index reach -14 nT. Maximum Kp index during the week was 2, as well as the local K index from Sumedang observatory reached 3. Substorm occurred at the beginning of the week with duration between 3 to 5 hours the intensity of Ae index showing the value less than 1000 nT. Throughout the week, the electron flux were on the high level around 1000 [/cm2/sec/sr].
Ionosphere conditions in this week were in quiet level to moderate level.
There ware depression of foF2 more than 30% from its median that lasted for 3 hours during this week. The foF2 depressions were impacted to the radiowave propagation over the ionosphere which known as the MUF Depression. The minimum frequencies (fmin) of the ionosphere in this week were in quiet condition. There increment of fmin could be a source of disturbance in the HF radio communication which known as the Shortwave Fadeout (SWF) or Radio Blackout (RB). Based on the ionospheric observations using GISTM over Bandung, the scintillation (S4) condition for this week were in quiet to moderate level. The error positioning conditions were in normal level condition that determined by the index W values.
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