Comparison between the arrival times predicted
using the HAFv.2 model of flare related
particles/shocks associated with the disk
passage of Active Region 0930 in December
2006 and the measured arrival times of these
disturbances at Earth, Mars and Venus
S.M.P. McKenna-Lawlor1, M.Dryer2,3, C.D. Fry2, Z. Smith3, M. D. Kartalev4, W.
Sun5, C. S. Deehr5, K. Kecskemety6, K. Kudela7, S. Barabash8, Y. Futaana8, R.
Lundin8 and R. Courtney9
1 Space Technology Ireland, National University of Ireland, Maynooth, Co. Kildare, Ireland (E-mail;
2 Exploration Physics International, Inc., Huntsville, Alabama, 35806, USA.
3 NOAA Space Environment Center, Boulder, Colorado, 80305, USA.
4 Institute of Mechanics, Academy of Sciences, 1113 Sofia, Bulgaria.
5 Geophysical Institute, University of Alaska, Fairbanks, Alaska, 99775, USA.
6 KFKI Research Institute for Particle and Nuclear Physics, Budapest, Hungary.
7 Institute of Experimental Physics, Kosice, Slovakia.
8 Swedish Institute of Space Physics, Kiruna, Sweden
9 Space Operations Centre, Air Force Weather Agency, Omaha AFB,
Omaha, Nebraska, USA.
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 1
Active NOAA Region No. 0930 which transited the solar east limb on 5
December, 2006 (S06o, ~E90o), was associated during its disk passage in the
minimum phase of Solar Cycle 23 with the production of significant solar
flares, energetic particles and coronal mass ejections.
The predicted arrivals at the Earth (1 AU), Mars and Venus of shocks generated
during four of these events in December, 2007 were estimated using the
Hakamada-Akasofu-Fry version 2 (HAFv.2) model and compared with in-situ
observations recorded at each of the planets.
Correspondences found between the predicted and observed arrival times of
these particle/shock signatures at particular spacecraft are discussed in the
context of developing capability to forecast the arrival of solar disturbances at
different locations within the heliosphere.
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 2
The HAFv.2 Model provides real-time operational forecasts of the disturbance-
driven solar wind through employing a modified kinematic approach to
simulate SW conditions.
In this scenario, fluid parcels are emitted along radials from the rotating Sun.
The spatial distribution of speed on the Sun-centered, spherical inner
boundary is non-uniform. The speeds of the particles along a particular
radial consequently vary as higher and lower-speed streams sweep past a
particular radial as the Sun rotates.
If magnetic flux conservation and a highly conducting solar wind plasma are
each assumed, this leads to a frozen-in field condition which prohibits
higher-speed streams from overtaking streams with slower speeds.
Solar wind acceleration/deceleration is accounted for by introducing a set of
parametric equations. Internal algorithms adjust fluid parcel positions to
account for fast stream-slow stream interactions, compression of the plasma
and evolution of the IMF . For details see Hakamada and Akasofu (1982)
Note that the internal free parameters of the model were set following an early
calibration with 1-D and 2-D MHD models/empirical studies and these are
held constant (Fry et al., 2007).
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 3
Potential Field Source Surface (PFSS) maps provide solar wind speed and radial
magnetic field on the HAFv.2 inner boundary [See Wang and Sheely (1990);
Arge and Pizzo (2000)].
Proxy parameters for significant disturbance drivers are solar optical, X-ray and
radio events that are accompanied by a reported shock (or CME) with a
speed of at least 400 km/s.
INDIVIDUAL EVENT PARAMETERS
• Optical/X-ray Event start time (taken to be within 0.5h of the accompanying
• Disk location of the parent solar event
• Event duration (piston driving time of shock: determined from the GOES soft
X-ray profile of the flare)
• Shock start (determined from metric Type II radio burst data)
• Initial speed (Vs) of the shock near the Sun (estimated from reported metric
Type II speed, or plane of the sky CME speed)
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 4
In the terminology of predictive modeling, the performance of
a model in predicting shock arrivals is expressed in the following terms:
HIT: Shock predicted and observed to arrive at a particular
heliospheric location within ±24h of its observed detection time.
MISS: Shock detected at a particular heliospheric location but
predicted to arrive at a time more than 24h
before or after this detection, or predicted not to arrive at all.
FALSE Shock predicted to arrive, but not detected, within a
ALARM window of 1-5 days (Earth) following a particular solar event.
CORRECT Shock neither predicted nor detected at a particular heliospheric
NULL location within a window of 1-5 days (Earth) following a particular
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 5
Temporally close shocks can potentially interact. In the simplest case involving
two interacting events, the predicted arrival of the second shock is either at the
same time, or earlier, than that of the preceding event. To take account of such
a pair of interacting shocks, the definitions presented previously are modified.
As before each shock is assigned a hit (h), miss (m), correct null (cn) , false
alarm (fa) and correct null (cn) classification. However, only one hit is
recorded and the contributing event is assigned to the category ‘correct null’.
For the present paper, the arrival times at Earth, Venus and Mars of flare related
shocks identified exiting the Sun (using metric radio burst drift data) during
the disk passage of Active Region No. 0950 were forecast in near-real time
using the Hakamada-Akasofu-Fry Model, version-2/(HAFv.2).
These predictions are compared with the measured arrivals at L1, Mars and
Venus of shocks recorded in plasma and magnetic data aboard the ACE,
SOHO, Mars Express, Venus Express and GOES spacecraft. The influence of
interplanetary conditions in determining the outcome at individual planetary
targets is discussed having regard to the prevailing geometry.
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 6
(Top left) East limb
passage of Active Region
0490 recorded aboard
TRACE. (Top right) Full
recorded by the Michelson
Doppler Imager (MDI)
aboard SOHO. (Bottom)
MDI Potential Field Source
Surface plot showing field
lines out to 2.5 Rs.
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 7
(Top right) An X9 flare at
S07, E79 was recorded
aboard GOES 12 on X-rays
December 5 (10.34-12.15
UT), followed on December
6 (1842-1854 UT at S 04 E
64 by a further X 6.5 flare.
(Bottom right) shows GOES
gradually rising protons
recorded aboard GOES 11.
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 8
(protons) recorded by
SOHO of a (relatively
rare) increase in
protons up to MeV
with the east limb
flares in Region 0490.
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 9
• The flare of December 5 (10.34-12.15 UT)
was accompanied by a Type II metre wave
burst with shock velocity 836 km/s. (Station
SVI/San Vito, Italy).
• The later flare of December 6 (18.42-18.54
UT) was accompanied by a further Type II
burst with shock velocity 2000 km/s (Rec.
aboard STEREO/ WAVES, private
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 10
Magnetic, energetic proton and
solar wind data recorded aboard
ACE during December, 2006 (Top
panel) note the arrival of a shock in
MAG data at 04.11 UT on
The SWEPAM/SW Level 1 data
(density, vel. temp) are unreliable
from ~ 07.00 UT, December 7
until ~16.00 UT on December 8 and
again on 13 December 13 ( ~ 13.40
- 18.00 UT) due to the prevailing
high proton background
Note that a second shock arrived on
December 14 at 13.52 UT
and a third shock on December 16
at 17.21 UT
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 11
On December 13 an X3.4 flare occurred in the same
active region (at S06, W23) See the GOES 11 and
GOES 12 X-ray fluxes (left) and EIT picture of the
flare location (right)
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 12
A well defined proton
enhancement (> 50
MeV protons) on
indicates that the
magnetic field was
well connected on
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 13
An associated metric Type
II burst was recorded at
Learmonth (1534 km/s).
LASCO reported a full
disk, asymmetric halo
event (seen here projected
from behind the occulting
disk). Also a partial halo
(> 120o) was projected out
of the ecliptic plane.
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 14
A shock associated with the December 13
flare arrived at L1 at 13.36 UT on
December 14. Solar wind speeds increased
from 600 to approx. 950 km/s. The Bz
component oscillated from + 15 nT to – 15
nT between 14.00 -18.00 UT (shock
compression of the IMF in front of a
magnetic cloud). From 18.00-22.00 UT the
Bz component was uniformly north
(maximum deflection ~ 15 nT). It then
shifted (uniform deflection ~ 18 nT) and
the field remained open until about 21.00
UT on December 15 as the magnetic cloud
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 15
An X 1.5 flare ( 22.10-22.22 UT) occurred on
December 14 (S06.W36). An associated metric
Type II burst was recorded at Culgoora (1600 km/s).
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 16
A proton event which was an order of magnitude weaker than in
the case of the previous flare (max flux 13 pfu at E > 50 MeV )
occurred. Also an asymmetric full halo was reported by LASCO
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 17
A weak shock and
magnetic cloud reached
L1 in association with the
flare of December 14 at ~
17.00 UT on December
16. Solar wind speeds
increased from 550 km/s
to ~ 750 km/s and BT
increased to ~ 10 nT. The
Bz deflections were
mostly to the north
throughout the enhanced
period and there was, thus,
a general lack of
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 18
Modeling of Shock Arrival at L1
(HAFv2 SW model)
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 19
Modeling of Shock Arrival at L1
(HAFv2 SW model) continued
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 20
• The HAFv.2 model indicated that disturbances associated with
the X9 and the X6.5 flares on December 5 and 6 interacted
with each other to produce a composite shock that was
predicted to arrive at L1 on December 7 at 08.00 UT. A shock
was recorded in ACE data on December 8 at 04.11 UT, some
20 hours late but within the period of ± 24 hours considered to
constitute a “hit” in making such predictions.
• On December 14, a shock predicted by HAFv.2 to arrive at
13.56 UT was detected at 14.00 UT in ACE data (hit).
• On December 16 a shock predicted to arrive at 12.00 UT
was recorded in ACE data at 17.22 UT about 5.5 hours late
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 21
Locations of the inner planets
relative to the Sun during
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 22
Measurements at Venus and
• The ASPERA 3 and ASPERA 4 instruments aboard Mars Express (MEX) and
Venus Express (VEX) are each composed of four similar instruments
• NPI (Neutral Particle Imager) measures the integral energetic neutral atom
(ENA) flux with no mass and energy resolution but with high angular resolution.
• NPD (Neutral Particle Detector)
resolves mass (hydrogen and oxygen) and velocity (energy range 0.1 - 10 keV)
of the ENA.
• EIS (Electron and Ion Spectrometer)
determines the electron and ion distributions at energies up to 40 keV
• IMA (Mass resolving Ion Analyser)
measures the main ion components (H+, H2+, He+, O+), molecular ions from 20
to 80 amu/q and up to 106 amu/q for dusty plasmas in the energy range from 100
eV to 40 keV/q.
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 23
• Aboard MEX, ASPERA-3 data are typically
recorded close to the Bow Shock crossings in
3-4 hour intervals.
• On VEX, ASPERA-4 observations are
typically made 60 min before and after the
inbound and outbound bow shock crossings.
Since VEX only observes at pericenter there is
a data gap of about 20 hours between
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 24
Ecliptic plane plots generated by
HAFv.2 showing solar wind
conditions at Earth, Mars and Venus.
IMF pattern: toward field lines
(blue); away field lines (red).
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 25
The largest flare in the sequence (X9/FF 663) began on
December 5 at ~ 10:34 UT. Neither ASPERA-3 or 4
were functioning at this time. However, ASPERA-3
detected an extremely high background level of ions
and electrons at Mars from 14:00 UT when the next
sequence of spacecraft operations was initiated. This
enhancement endured for at least 3 days (i.e. spanning
the occurrence of the X6.5/FF 664 flare of December 06
at ~ 18.42 UT and was present until Mars entered an
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 26
On December 8 the eastern flank of interacting
FF events 663 and 664 was predicted by
HAFv.2 to arrive at Venus between 03.00-05.00
UT. Put in Ghee pictures for December 8
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 27
There was a gap in the ASPERA-4 observations
from December 07 at 10.00 to December 08 at
05.30 UT and the shock was not observed in the
data recorded thereafter. However, following
05.30 UT time the background ions were found
to have substantially increased in energy since
the previous day
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 28
The HAFv.2 model
predicted that, on
December 20 at 00.00 UT,
the shock accompanying
FF event 666 overtook that
of event 665 just as the
western flank of these
interacting shocks reached
Mars There was also a
field reversal at this time
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 29
The ASPERA-3 ion data
show a signature of heating
between December 19
(23:45UT) and December 20
(04:00UT), indicating the
arrival during that interval at
Mars of an interplanetary
shock. The arrival time of this
shock is in good conformity
with the prediction of
HAFv.2. By December 21 the
solar wind had recovered to a
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 30
• HAFv.2 has previously been shown to provide useful predictions
of shock arrivals at Earth (e.g. Fry et al., 2003, McKenna-Lawlor
et al., 2006) and, in the present case the model has provided
predictive hits with regard to shock arrivals measured at L1 in
association with the flares of December 5, 6, 13 and 14, 2006.
• Consideration of HAFv.2 predictions in relation to in situ
measurements made at Mars by ASPERA-3, again suggest the
usefulness of these predictions in the case of an event on
December 20 when the Earth and Mars were located on opposite
sides of the Sun.
• A prediction by HAFv.2 of the arrival of a shock at Venus
required more continuous observations than were available in
ASPERA-4 data to monitor its arrival. A hint of a possible in situ
response to the predicted disturbance may be contained in the
presence in ASPERA-4 data later on the day concerned of a
significantly enhanced particle background.
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 31
• A reasonably accurate description of pre-event
heliospheric conditions made by utilizing the PFSS
method and the HAFv.2 code is now to hand. A full
3D MHD global description of conditions at the Sun
which will provide improved pre-event simulations is
• Definitive validation of predictive models at Venus
and Mars requires for their implementation
continuous observations at these planets.
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 32
5th SECCHI Meeting LAL, Orsay, France. March 5-8, 2007 page 33