2010-05-07 11:15:15

The First Geomagnetic Effect of new 24th Solar Activity Cycle detected at Aragats Space Environmental Center (ASEC)

A geomagnetic storm began at 08:55 UT on Monday, April 5, 2010. Space weather storm levels reached Strong (G3) levels on the Geomagnetic Storms Space Weather Scale. The source of the storming is an Earth-directed Coronal Mass Ejection associated with a weak solar flare that occurred in Active Region 1059 on April 3 at 08:54 UT. The event registered Kp = 7 on the 0-to-9 Kp index scale of magnetic disturbances. 

  Figure 1 The 2.5% count rate increase of the Nor Amberd neutron Monitor inverse correlated in time with the minimum of the geomagnetic field strength measured by the Nor Amberd  magnetometer.

 

As we can see in the Figure during minimum of the geomagnetic field strength (measured by '' LEMI-018 magnetometer) additional Galactic Cosmic Rays enter the atmosphere producing some extra hadrons in interactions with terrestrial atmosphere. These secondary hadrons incident on Neutron Monitor enlarge the count rate by 2.5%.

A bit bigger peak was detected also by Aragats Neutron Monitor- the same type as the Nor Amberd one – 18 NM64. Other ASEC detectors are sensitive to higher energies of primary particles and decrease of the geomagnetic field did not change their count rate. The Neutron Monitors are sensitive to energies just above the cutoff rigidity; therefore decrease of cutoff rigidity leads to increase of count rate.