Space Science Center
National Institute of Aeronautics and Space
LAPAN - Indonesia



Periode: June, 1st – 7th 2018


The Sun condition has been quiet for the past weeks as it has entered a minimum activity phase. During the past week, there was only one active region seen with relatively small size, namely NOAA 2712. After once produced C-class flare on the last May 28, this active region produced C1.0 flare again on June 6, at 10.44 UT.  Aside from the flares, there was no noteworthy activity such as filament eruption as well as halo or partial halo CME occurred within the past week. However, solar activity next week may be rising since the latest STEREO A observation revealed an active region which is expected to emerge from the east limb of solar disk in the next 2-3 days.


Geomagnet conditions on June, 1st – 7th 2018 began with active condition on 1 June 2018 which then followed by quiet condition untul 7 Juni 2018. The active condition caused by high speed stream came from geoeffective coronal hole at solar equator . Minimum Dst index reached -35 nT, maximum kp index was 5 which means there was minor storm condition at high and mid latitude at that time. While  local response for Indonesia region from Kupang observatory based on K index reached its  maximum value 4. Farther on 2-7 June 2018 the geomagnetic condition in Indonesia return to quiet level. By the time of active condition, there was substorm occurrence with intensity less than 1500 nT, occurred for 13 hours. Substorm still going on over the next few days with lower intensity, until 4-6 June 2018 the substorm activity ended. The substorm activity  reoccurred on June 6, 2018 at 14:00 UT to 7 June 2018 at 04.00 UT with an intensity of less than 1000 nT.


Ionosphere conditions in this week were in quiet level.

There was no depression of foF2 more than 30% from its median during this week. The foF2 depression that affect to the radiowave propagation over the ionosphere which is known as the MUF Depression did occur in this week. The minimum frequencies (fmin) of the ionosphere in this week were in quiet condition. There was increment of fmin could be a source of disturbance in the HF radio communication which is known as the Shortwave Fadeout (SWF) or Radio Blackout (RB). Based on the ionospheric observations using GISTM, the S4 index value (scintillation condition) was less than 0.25. The error positioning conditions were in slight level condition that determined by the index W values.

Keyword : solar-activity, geomagnetic-activity, ionospheric-condition, space-weather
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