Solar wind summary (Last 24 hours)

31 March


Solar wind parameters were at background levels. Solar wind speeds were
steady in the 370-440 km/s range, total field strength values were
steady between 1-4 nT, and Bz reached a maximum southward component of
-4 nT. Phi data was predominately steady in a negative (toward) sector
for the first half of the period and changed to a predominately positive
(away) sector for the remainder of the period.

30 March


Solar wind parameters were at background levels. Solar wind speed was
steady in the 400-470 km/s range. Total field values varied between 1 -
5 nT and the Bz component briefly reached a maximum southward value of
-4 nT. Phi data was oriented in a negative (toward) sector throughout
the period.

29 March


Solar wind parameters were indicative of a continued nominal solar wind
environment. Solar wind speeds were steady in the 380 – 480 km/s range.
Total field strength values peaked at 6 nT while the Bz component
reached a maximum southward component of -5 nT. The phi angle was
predominately negative (towards) throughout the period with only short
deviations to the positive (away) sector.

28 March


Solar wind parameters were indicative of a nominal solar wind
environment. Solar wind speeds were steady in the 350-450 km/s range
with only short periods of speeds reaching close to 500 km/s. Total
field strength values ranged from 1 – 8 nT while the Bz component
ranged from +8 nT to -5 nT. The phi angle transitioned from a negative
(toward) sector to a positive (away) sector at around 27/1800 UTC but
became variable after about 28/0100 UTC.

27 March


Solar wind parameters continued under the waning influence of the 23 Mar
CME. Solar wind speeds ranged from 355 km/s to 415 km/s through 26/2214
UTC. At 26/2215, a small increase in total field (4 nT to 9 nT) with a
corresponding increase in wind speed to near 430 km/s was observed.
Solar wind speed increased briefly again to 450 km/s at 27/0447 UTC
before decreasing to end-of-period values near 400 km/s. Total field
decreased to near 4 nT by the end of the period with a prolonged period
of southward Bz near -4 nT beginning at 27/0745 UTC. Phi angle began in
a positive (away) sector until 26/1600 UTC when it transitioned into a
mostly negative (towards) sector. By approximately 27/0600 UTC, phi
angle deviated briefly into a positive sector.

26 March


Solar wind conditions were at nominal levels until a shock arrival was
observed in ACE data at 25/1925 UTC, announcing the arrival of the 23
Mar CME. Solar wind speeds increased from approximately 375 km/s to 500
km/s and the total field was enhanced from +2 nT to a maximum value of
+13 nT. The Bz component turned southward following the arrival with a
maximum southward deflection of -10 nT at 25/1938 UTC, and then became
variable in the +9/-8 nT range. Solar wind speed reached a maximum of
554 km/s at 26/0049 UTC before decreasing to end of period values near
410 km/s. Phi angle varied from positive (away) to negative (towards)
sectors through approximately 26/0510 UTC when it settled into a
positive orientation.

25 March


Solar wind speeds continued to decrease through the period from
approximately 470 km/s to end of period values near 380 km/s. Total
field ranged from 2 nT to 6 nT with the Bz component between +5 nT and
-4 nT. Phi angle was mostly positive (away) until 25/0848 UTC when
brief deviations into a negative (towards) sector occurred.

24 March


Solar wind parameters were indicative of continued weak influence of a
positive polarity coronal hole high speed stream (CH HSS). Solar wind
speeds were steady in the 435-545 km/s range. Total field strength
values ranged from 2 nT – 6 nT while the Bz component ranged from +5 nT
to -4 nT. The phi angle remained steady in a positive (away) sector
throughout the period.

23 March


Solar wind parameters indicated the likely onset of a weak positive
polarity coronal hole high speed stream (CH HSS). Solar wind speed
peaked near 550 km/s but gradually decreased and held steady between 450
km/s – 500 km/s. Total field strength values were steady in
the 4 nT – 10 nT range while the Bz component ranged from +9 nT to -4
nT. The phi angle remained in a mostly positive (away) sector
throughout the period.

22 March


Solar wind speeds, measured by the ACE spacecraft, began the period at
nominal levels. A solar sector boundary change from negative (towards)
to positive (away) was coincident with a rise in temperature and wind
speed beginning just before 0100 UTC. Solar wind speeds gradually
increased from approximately 350 km/s at that time to end of period
speeds around 450 km/s. This is indicative of the early effects of a
geoeffective coronal hole high speed stream (CH HSS). IMF total field
ranged from 2 nT to 10 nT while Bz remained mostly positive but varied
between -5 nt and +9 nT.