21st August

Solar wind parameters observed at the ACE spacecraft indicated the
waning influence of the magnetic plasma cloud from the CME observed
leaving the Sun on 15 Aug. The total magnetic field began near 20 nT at
the beginning of the period and had declined to about 7 nT by 21/1000
UTC. Bz remained positive until about 20/1849 UTC, after which it
fluctuated between positive and negative values, reaching a minimum of
-9 nT at 20/1854 UTC and ending near -5 nT. Phi rotated slowly from
negative to a positive orientation. Solar wind speed at ACE generally
remained between 360 and 310 km/s.

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