Extreme Solar Flares and Resultant
Extreme Ionospheric Effects
A. R. Jones1, D. L. Judge1, M. Harmon1, B. T.
Tsurutani1,2, F. L. Guarnieri1,2, G.A.
Zambon1, A. Mannucci2, B. Iijima2, G. Hajj2
1
University of Southern California, Los Angeles, CA.
2 Jet Propulsion Laboratory, Pasadena, CA.
These initial findings were presented by Tsurutani et al. at the Conference on Sun-Earth
Connections:Multiscale Coupling in Sun-Earth Processes February 9-13, 2004
Some of the most intense solar flares in recorded history
occurred at the end of 2003. The November 4th event is the
largest on record (X28) and the October 28th flare was the
fourth most intense (X17). These will be compared/contrasted
to the July 14, 2000 Bastille Day (X6) event.
We use SOHO EUV (SEM), and high time resolution, ~1s
ground base GPS data to examine the abrupt increase in pathintegrated ionospheric total electron content (TEC). It will be
shown that the dayside ionosphere responds dramatically to
the X-ray, FUV and EUV input by an abrupt ~20-40%
increase in ionospheric electron densities. The TEC increases
are nonlinearly related to the peak flare intensities. The
reasons for this are not understood at this time.
Bastille Day
July 14th 2000 Flare in Central-Order
250000
SEM 07-14-00
200000
Counts
150000
100000
50000
0
2451739.5
2451740.0
Julian Date
2451740.5
DIF-DAY 7-14-00
HRAO 07-1400
October 2003
SEM 10-28-03
Oct. 28 - 31 th. 2003 Flares in Central-Order
250000
200000
Counts
150000
100000
50000
0
2452940.5
2452941.0
2452941.5
2452942.0
Julian Date
2452942.5
2452943.0
DIF-DAY 10-28-03
NKLG 10-2803
November 2003
November 4th 2003 Flare in SEM Central-Order
300000
250000
SEM 07-14-00
Counts
200000
150000
100000
50000
0
2452948
2452948
2452949
2452949
Julian Date
2452950
2452950
DIF-DAY 11-04-03
RIOG 11-04-03
Conclusions
1.
2.
3.
Solar Flares can have extreme effects on the Earth’s ionosphere. Abrupt
increases of ~25 x 1016 electrons/m2 (25 TECU) can occur in 5 minutes.
This corresponds to a ~ 25% increase in ionospheric electron content.
The X-ray/EUV spectrum of flares is highly variable. In the 1-8 A X-ray
wavelength range (GOES satellite), the largest flare is Nov 4, 2003 (X28)
followed by Oct 28, 2003 (X17) with the Bastille day event (July 14, 2000)
last (X6). In the SEM .1-50nm wavelength range, the Nov 4 event is the
largest, followed by the Bastille Day event, and Oct. 28, last.
Although abrupt TEC enhancements followed all three flares, the relative
responses were different from that of either the X-ray or EUV events. The
October 28, 2003 TEC increase was ~3 times that of the Nov. 4 or Bastille
Day events. The dayglow increase of October 28 was ~2 times more intense
than that of the November 4 event. These features are not presently
understood. We will be continuing our effort to understand the flare spectral
variability and ionospheric responses in the future.
Future Work
•
•
•
Look at a wider range of flares an
ionospheric responses.
GPS tomography to provide 3-D electron
density maps of the ionosphere.
Ionospheric models using the flare input
data will be used to compared against
tomographic analyses of the GPS
information.