NOAA/USAF SEC Highlights of Solar and Geomagnetic Activity 04 – 10 September 2000

Solar activity was at low levels during the period. Isolated to
occasional C-class subflares occurred during much of the period from
a number of mostly small, simply-structured sunspot groups. The
largest event was a C9/1N at 01/1820 UTC from Region 9140 (N11, L =
079, class/area Dao/130 on 01 September). Region 9149 (N14, L = 356,
class/area Eai/240 on 03 September) was the largest region on the
disk at the end of the period. However, this region has shown no
significant changes and has produced only isolated C-class
subflares. Region 9154 (S21, L = 328, class/area Bxo/020 on 03
September) was in a growth phase at the end of the period and
produced C-class subflares. The remaining regions were mostly small
and stable at the end of the period.

Data were available from the Advanced Composition Explorer (ACE)
spacecraft for most of the period. Velocity was moderately high and
density was low for most of the period. These conditions were
consistent with the high-speed coronal hole stream that was the
dominant solar wind event during the period.

There were no proton events detected at geosynchronous orbit during
the period.

The greater than 2 MeV electron flux at geosynchronous orbit was at
high levels (greater than 1000 pfu) during the period 30 August to
02 September. The greater than 2 MeV electron flux was at normal
levels for the rest of the period.

The geomagnetic field was at quiet or unsettled to active levels
during most of the period. Major storm conditions occurred on 29
August and a brief period of minor storming occurred on 02
September. These conditions were caused by a high-speed,
positive-polarity, coronal hole stream. Geomagnetic activity
declined to quiet to unsettled on the last day of the period.