Solar wind summary (Last 24 hours)

10 January


The 07 Jan CME appeared to arrive at the ACE spacecraft at 09/1932 UTC
when density, temperature and wind speed exhibited weak enhancements.
Wind speed values prior to the CME arrival were at approximately 400
km/s and became elevated to a high value of 527 km/s at 09/1947 UTC.
Wind speeds only remained elevated for a short period before returning
to the 400 km/s range just after 10/0300 UTC. The total interplanetary
magnetic field (IMF) exhibited a weak but sudden enhancement to 16.7 nT
at 09/1956 UTC, but have since returned to near 5 nT. The Bz component
of the IMF had a minor deflection to -4 nT at the time of the impulse,
but recovered to positive territory quickly and remained mostly positive
throughout the period. The phi angle was oriented in a mostly positive
(away) solar sector with brief fluctuations into a negative (towards)
orientation.

9 January


Solar wind parameters, as measured by the ACE spacecraft, reflected
fairly benign conditions. Solar wind speeds were steady near 350 km/s
for the first half of the period. Just after the turn of the UTC day,
speeds began a slow but steady rise to near 455 km/s with an isolated
peak speed of approximately 490 km/s. Speeds then slowly decreased to
just under the 400 km/s mark, where they remained though the end of the
period. The IMF total field ranged between +1/+9 nT and ended the period
at a steady +7 nT. The Bz component varied between -3/+4 nT for the
first part of the period, then increased in variability to -7/+6 nT
before settling back at near neutral to end the period. The phi angle
began the period in a predominantly negative (towards) orientation, then
oscillated to a mostly positive (away) angle for remainder of the
period.

8 January


Solar wind parameters, as measured by the ACE spacecraft, indicated the
arrival of the anticipated weak CME from 04 Jan. Solar wind speed
started the period at 350 km/s, then indicated a sharp increase to 435
km/s at 07/1428 UTC with arrival of a sudden impulse from the 04 Jan
CME. Speeds then began a steady decrease throughout the period, ending
at a fairly constant speed near 325 km/s. An increase in density,
temperature and wind speed accompanied an enhancement in the
interplanetary magnetic field (IMF). The IMF total field reached a peak
of 8.6 nT while the Bz component saw a maximum southward deflection of
-7.7 nT. The phi angle remained in a predominantly positive (away)
orientation for most of the period, with isolated oscillations into
negative (towards) territory near the end of the period.

7 January


Solar wind parameters, as measured by the ACE spacecraft, were a
reflection of a waning CH HSS. Solar wind speed started the period
near 360 km/s and displayed a nearly consistent speed between 340 km/s
and 370 km/s, finishing at approximately 350 km/s. Total interplanetary
magnetic field (IMF) ranged between +1 to +4 nT. The Bz component of the
IMF was predominately south and had a maximum deflection of
approximately -3 nT. The phi angle was in a predominantly positive
(away) orientation for the first half of the period, with isolated
oscillations into negative (towards) territory during the last half.

6 January


Solar wind speed at the ACE spacecraft continued to decline, from 450
km/s at the beginning of the period to near 350 km/s by the end, as the
high speed stream waned. Phi remained positive throughout and the IMF
was benign. Bt was at or below 5 nT and Bz never dipped below 4 nT.

5 January


Solar wind speed at the ACE spacecraft slowly decline through the period
to end near 450 km/s, signalling the end of the high speed stream. ACE
remained in a positive solar sector under benign magnetic conditions.
Bt remained at or below 5 nT and Bz never dropped below -5 nT.

4 January


Reflecting the coronal hole effects, solar wind speed at the ACE
spacecraft remained near 500 km/s. The phi angle was positive
throughout the period. Bt ranged from 4-6 nT. Bz ranged from -5 nT to
5 nT.

3 January


Solar wind at ACE began near 550 km/s and increased to a peak of 666
km/s around 02/2100 UTC. It began to decrease afterwards, ending the
period in the low to mid 500 km/s range. The phi angle was generally
positive (away) most of the time. Bt ranged from 2-8 nT while Bz dipped
to -6 nT early in the period. These observations were consistent with
the declining influence of a coronal hole high speed stream.

2 January


Data from the Advanced Composition Explorer (ACE) spacecraft indicated
the continued influence of a positive-polarity CH HSS. Wind speed
started the period at 412 km/s, reached a high of 608 km/s at 01/2127
UTC, and ended the period at approximately 540 km/s. IMF Bt hit a high
of 17 nT at 01/1335 UTC, then began to gradually decrease. IMF Bz ranged
between 9/-14 nT. IMF Phi data indicated a positive-polarity (away)
solar-sector orientation during the period.

1 January


Solar wind parameters measured at ACE were predominately indicative of
background solar wind conditions. The phi angle indicated the influence
of a positive (away) orientation through most of the period. At
approximately 01/0930 UTC the phi angle switched to a negative (towards)
orientation and wind speed began a steady climb from approximately 375
km/s to a high of 447 km/s at 01/1136 UTC. The total interplanetary
magnetic field reached a peak value during this same timeframe of 16.2
nT while the Bz component subsequently dropped as low as -12.9 nT.
Analysis would indicate that we are beginning to see the effects of a
negative-polarity, coronal hole high-speed stream (CH HSS).