Docstoc

McKenna-Lawlor_Orsay 2007-03-Paris

Document Sample
McKenna-Lawlor_Orsay 2007-03-Paris Powered By Docstoc
					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;
     stil@nuim.ie ).
 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
   shock start)
• 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
                 solar event.

5th SECCHI Meeting                       LAL, Orsay, France. March 5-8, 2007 page 5
   Interacting Events
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
                            disk magnetogram
                            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
                                                                  GOES
  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
                                                                  protons
  gradually rising protons
  recorded aboard GOES 11.

5th SECCHI Meeting          LAL, Orsay, France. March 5-8, 2007 page 8
Particle profile
(protons) recorded by
the EPHIN
instrument aboard
SOHO of a (relatively
rare) increase in
protons up to MeV
energies associated
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
    communication ).

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
December 7.
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
(snowstorm- effect).
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
December 13
indicates that the
magnetic field was
well connected on
this day.




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
moved through.


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
connectivity.
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
        HAFv.2 Predictions
  • 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
    (hit).

5th SECCHI Meeting               LAL, Orsay, France. March 5-8, 2007 page 21
        Locations of the inner planets
         relative to the Sun during
               December 2006




5th SECCHI Meeting        LAL, Orsay, France. March 5-8, 2007 page 22
    Measurements at Venus and
             Mars
• 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
    measurement sets.

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
  ‘away’ sector.
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
cool beam.


5th SECCHI Meeting                LAL, Orsay, France. March 5-8, 2007 page 30
                 Conclusion
• 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
       Conclusion continued
  • 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
    awaited.
  • 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

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:12
posted:4/9/2012
language:
pages:33