1. Large Magnetic Impulse Events
Martin Connors, Athabasca University/U. Calgary Sébastien Guillon, Hydro-Québec TransÉnergie Mark Engebretson, Augsburg University Kyle Reiter, Brian Jackel University of Calgary David Boteler, NRCan
C.T. Russell, R.L. McPherron, UCLA
SCOSTEP STP14, Toronto, July

2. Large Impulsive Magnetic Events
LIME
Large Impulsive Magnetic Events
What's in a name? That which we call a rose By any other word would smell as sweet;
Juliet, in Shakespeare

3. Two new geophysical instruments in eastern Canada 1) Hydro Quebec grid 2) AUTUMNX magnetometer network

4. Aspects of Spikes You Might Like
If you are finding ground magnetic data boring, a good spike may be all you need to pique your interest!
Aspects of Spikes You Might Like

5. The Big Spike Dislike = dB/dt
NASA

6. December Spike -> dB/dt near Québec’s major generation facility not a good thing we think! Seen worldwide but most intense in auroral zones

7. GOES conjugate to AUTUMNX sees compression of B Low energy protons “new radiation belt”
(GOES data: Howard
Singer/NOAA)

8. AUTUMNX
Large (all units nT) perturbations were observed at AUTUMNX stations in the auroral zone, and GOES field rotated as well as showing compression.
(GOES data: Howard Singer/NOAA)

9. Equivalent Currents and BZ
Equivalent current arrows [(BX,BY) rotated 90°] and BZ [saturates +(red) at 300 nT and -(blue) at -300 nT] “moving over” AUTUMNX for the Dec event. Longest arrows are also about 300 nT.
SALU
IONOSPHERIC CURRENT
PUVR
INUK
SNKQ
KJPK
RADI

10. Hydro-Québec Harmonic Distortion % Indicating GIC flowing in Grid (1% is “bad”)
11:15-11:23
Time zoom
SMDA Station “O”

11. SI events can occur anytime, but Harmonic Distortion is mostly at night
Over a three year period, events above the 1% threshold at one or more stations took place ~monthly.
We find that there are at least four classes of MIEs:
SI (pressure pulses)
Solar wind rotation events
PBIs (poleward boundary intensifications)
Substorm-like events

12. There are Positive LIME too
Top is THD distribution as in previous slide. Green is all B spikes inferred from dB/dt. Negative spikes are in evening sector, positive spikes are in morning sector. Frey UV (substorm up FAC) more concentrated.

13. Turbulent Reverse Cascade in Flow Around Earth?

14. First “Prediction” of GIC (post-event) was a substorm-like event with emphasis on Z (vertically down) component LARGE (-1400 nT) Z spike noted at INUK at 2 UT (LT~21h) with |dBZ/dt| > 900 nT/min Upon inspection, 0.4% THD found at nearby monitor point
dBZ/dt > 900 nT/min

15. Impulsive signals seen at all regional stations
Westward electrojet-like signals at some (- X) Large -Y (westward) component at many Dominated by –Z to south, +Z to north, note that –Z is offscale at INUK and PUVR
Unusual auroral streamers in region of current flow as seen from SNKQ

16. Spatiotemporal Arrow Plot
Short-term activation of NW-oriented electrojet, possibly with Z-component enhancement from eastward electrojet A short substorm-like event at a strange angle like the associated streamer aurora

17. Magnetic Impulse Events Summary
We focussed on SI and an unclassified substorm-like impulse event. Both show large changes in Z (vertical) component. Both caused HD (GIC) in Hydro-Québec grid. Faraday’s Law says
Feb regional movie (preliminary)
01:45 to 02:15 UT eq. current/Z overlay
Figure: Geosci.xyz

18. Unusual streamer aurora, large Z (square) and poleward electrojet

19. Conclusions/Prognosis
AUTUMNX, in close proximity to the Hydro-Québec grid, has detected many magnetic impulse events (MIEs) AUTUMNX coverage of the auroral zone is best in North America (& conjugate GOES) Conjugate to Antarctica AUTUMN/AUGSO in west
Acknowledgements:
AUTUMN/AUGO/AUGSO installed, with partial operating funds from Canada Foundation for Innovation
AUTUMNX installed and operated with funding from the Canadian Space Agency.
Research support from the Canadian NSERC is acknowleged.
Merci!