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High Speed Stream
Catalog: M2M_CATALOG
Event Time: 2025-09-06T04:20Z ( ACE: MAG )
All Detecting Spacecrafts:
ACE: MAG
ACE: SWEPAM
Activity ID: 2025-09-06T04:20:00-HSS-001 (version 3)
Event End Time:
Peak Solar Wind Speed (km/s): 600.0
Date of first appearance of coronal hole in EUV at east limb: 2025-08-29
Note: Characterized by an increase in solar wind speeds from approx. 400km/s to approx. 600km/s beginning at 202-09-06T04:20Z. An increase in temperature ( approx. 140kK to 330kK) is also observed in conjunction with the increasing speeds. This coronal hole high speed stream signature is combined with the arrival of CME: 2025-09-04T20:30Z, which arrived at 2025-09-06T15:31Z, further enhancing the solar wind speeds to approx. 700km/s. On 2025-09-09, there was an additional increase in solar wind speed from approx. 450 km/s to approx. 550 km/s beginning around 2025-09-09T09:54Z likely caused by the connection to a different extension of the same positive polarity, southern coronal hole. This increase in solar wind speed was accompanied by a following period where all magnetic field components were negative. With emphasis on the negative B_z and B_y components, this could have been responsible for a brief period of geomagnetic storming. 
Version 1 submitted on 2025-09-09T16:51Z by Melissa Kane
Version 2 submitted on 2025-09-10T15:31Z by Elizabeth Juelfs
Version 3 submitted on 2025-09-10T15:34Z by Elizabeth Juelfs
No Notification has been sent for this activity yet.

All directly linked activities:
2025-09-09T14:15:00-RBE-001
2025-09-09T21:00:00-GST-001
NOAA Kp: 5.67 (2025-09-10T00:00Z)
2025-09-12T16:40:00-RBE-001


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