The Sun is entering its minimum activity phase, such that no eruptive events these days. There was only small active region NOAA 12723 that been seen since two week ago. There is a new region expected to emerge next week. Solar activity next week is predicted to be at quiet level.
In the period of October 5th – 11th the geomagentic conditions were on quiet level with 1 day of active condition. Geomagnetic active condition occurred at 7 October was indicated by K index from Manado and Kupang stations which reached 4. At the sam time, minimum Dst index reached -39 nT while Kp index reached 5 means that geomagnetic condition in high and mid latitude was on minor storm level. There is also an increment on substorm activities at auroral zone based on Ae index. Substorm started to occur on 7 October with intensity less than 1500 nT and it was occurred several times until 11 October duration between 3 to 14 hours. Source of geomagnetic disturbance that occurred on 7 October was high speed stream from coronal hole at pole that elongated to equator and that was geoeffective from 4 October 2018. After 7 October the geomagnetic condition return to its quiet level eventhough it still affected by the stream from coronal hole that caused the K index reached 3 several times.
Ionosphere conditions in this week were in moderate to strong level. The depression of foF2 lower than 30% from its median values occurred everyday. The foF2 depressions were impacted to the radio wave propagation over the ionosphere which known as the MUF Depression. There was increment of fmin of more than 30% from its median value every day. There was no disturbance in the HF radio communication which is known as the Shortwave Fadeout (SWF) or Radio Blackout (RB) due to Solar flare activity that remained in the quiet level. Based on the ionospheric observations using GISTM over Bandung, the scintillation (S4) condition for this week was in quiet level with S4 index value less than 0.25. The error positioning conditions were normal to slight levels conditions that determined by the index W values were between +/- 1 and +/- 2.
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