1. SPEED EVOLUTION OF CME/SHOCKS USING MULTI-SPACECRAFT OBSERVATIONS OF TYPE II RADIO BURSTS.
T. Manuel-Hernández, E. Aguilar-Rodriguez
and A. Gonzalez-Esparza
Instituto de Geofísica UNAM, Unidad Michoacán
I'm doing my first year PHD study in science physics at UNAM.
I’m interested in study of 1 1

2. * Objetive
To determine the propagation of large-scale disturbances in Solar Wind using interplanetary Type II radio burts observations, detected by Wind/WAVES and STEREO/SWAVES in the ascending phase of the solar cycle 24.
The main objetive this research is determine…
It’s know that… 2

3. Metric DH
Kilometric
* Objetive
Type II
emission
To determine the propagation of large-scale disturbances of Solar Wind by using Type II radio burts observations in the frecuency range DH-km, detected by Wind/WAVES and STEREO/SWAVES in the ascending phase of solar cycle 24.
Type II
emission
Interplanetary Type II radio burst result from the excitation of plasma waves in the ambient medium by shock waves driven by coronal mass ejection……
Near sun, is a paradigma, no yet verified wheter type II radio burst is caused by shock waves driven by CMEs o flares.
Then.. To determine the track the heliocentric evolution of fast CMEs and their shock…
CMEs driven shock
(Flares/CME)
CMEs driven shock
(Cane, 1987).
Type II radio burst 3

4. In this Study we have considered 24 IP Type II radio bursts observed by the three radio experiments and its corresponding solar event. In some cases we included the metric counterpart of each type II radio observed by ground-based radio intrument.
We analized list of Type II radio burst observed by STEREO/SWAVES and Wind/WAVES radio intruments. 4

5. by Wind/WAVES and STEREO/SWAVES
Type II radio bursts observed
by Wind/WAVES and STEREO/SWAVES
The properties of CMEs (Central position angle….) are seleted from CME catalog SOHO-LASCO
In the case of properties of CMES STEREO, we selected from CME catalog Cactus..
Unfortulately, the first months of observations of STEREO there weren't records of CMEs and other days there were data gaps. 5

6. How to track the heliocentric evolution of fast CME/shocks?6

7. CME/shock speed determination
Reiner et al., (1998) showed that if we asume that the shock speed is constant and the plasma frequency decays as 1/R2, then the Type II emission is organized along a straight line.
The frequency drift rate of a Type II emission generated by a CME-driven shock can provide direct measumerent of the shock speed.
Assuming that the schock speed (v) is constant during a short interval and the solar wind is decreasing as 1/R knowing the slope of the frecuency drift and the solar wind density at 1 AU (no) we can aproximate the speed of the shock causing the emission:
One under squar R
Years later Gonzales-Esparza and … apply a new technique to obtain shock speed estimates by analyzing Type II radio burst observed in the kilometric domain.
V is shock speed, n0 is the density normalized to 1AU, R0=1.5x10⁸ km, a=9 if the emission is Fundamental (F), and a=18 if the emission is harmonic (H). 7

8. Speed determination technique
(a) Type II radio burst dynamic spectrum.
(b) isolated Type II event.
(c) for every radio spectrum (1 min res.) we apply a Gaussian fit (dashed line) to the flux density distribution vs frequency to determine the central frequency.
(d) to study the frequency drift associated with the km-TII burst we select some intervals.
(e) we calculate the slope for subintervals of at last 60 minutes to obtain the speed solutions distribution
- report the mean speed
and its standard deviation
for the interval
Bisi et al two thousand used the technique. this Figure is a example of the resulta obtain…
First, we have…
Second step, we [aisoleired] .. And the program cut each minute the emision….
Letter C. for spectral measurements by plotting the flux density as a function of the observing frequency… we
Bisi et al., 2010 8

9. Speed evolution
Solid-Circle: Shock speed of the radio kilometric Type II burst drift.
Triangle: initial speed white-light
Solid-Diamond: speed interplanetary scintillation
This figure shows the speed evolutions of the CME. ..
The combination of the diferents measurements show a gradual tendency for the decelaration of the CME/Shock as it propagates to 1 astronomic unid.
Bisi et al., 2010 9

10. Cases Study
We took a sample of three Type II radio burst observed by the three spacecraft. 10

11. 1st case study: 2007/01/25 SOHO-LASCO Position of STEREO GOES
Time Central Angular Vel.
PA Width (km/s)
06: Halo
SOHO-LASCO
Position of STEREO
C6.3
The CME start at… the initial speed is about one thousand kilometer per second.
In this firs study case there wasn’t observations of CME by STEREO.
The CME is [releited] with flare of intensity C6.3 [loqueited] a limb east. In agrremint Ana Laskmi and Umapathy (2012) we clasifai the event as limb event.
GOES
Separation angle with Earth
Separation angle A with B
Loc A.R Clas Time
S08E C 11

12. Dynamic Spectra Central Frequencies
Type II radio burst
Int 1
Int 1
The observations the dinamics espectra by three radio experiment show a Type II radio burst intermitent..
Unfortunately STEREO-B had a data gap of about two hours 12

13. Speed evolution
Metric: The shock speed using the Newkirk’s density model.
SA-radio and Wind-RAD1:
obtained from the analysis technique using kilometric Type II radio observations.
The shock speed obtained from use the newkir’s density model.
obtained from the analilysis of the radio kilometric Type II burst drift.
Speed in situ obtained for the measuremets in-situ for plasma and magnetic field by STEREO
In soho-lasco liner fit show a desacelerations of m/s2.
We can see as combinations of the difetens measurements show a gradual tendency for the decelerations ot he CME/shock as ir propagates to Astronomic unit 13

14. 2nd case study: 2011/11/26 SOHO-LASCO 07:12 HALO 360 933
Time Central Angular Vel.
PA Width (km/s)
07:12 HALO
SOHO-LASCO
Position of STEREO
C1.2
We can sey that STEREO-A and B are behind the Sun
The CME start at… the initial speed is about nine hundred kilometer per second.
The CME is [releited] with flare of intensity C1.2. In agrremint Ana Laskmi and Umapathy (2012) we clasifai the event as intermediate event.
Such that the CMEs propagated between Wind and STEREO-B
GOES
Separation angle with Earth
Separation angle A with B
Loc A.R Clas Time
N08W C 14

15. Time Central Angular Vel.
PA Width (km/s)
07:
Time Central Angular Vel.
PA Width (km/s)
07:
SECCHI-B
SECCHI-A
SOHO-LASCO
This events was observed by three spacecrafd.
These movies show evolutions of each CMEs. In the three case the widh's CMEs is great.
Time Central Angular Vel.
PA Width (km/s)
07:12 HALO 15

16. Dynamic Spectra Central Frequencies
Type II radio burst
Int3
Int1
Int2
Type II radio burst
Int1
Type II radio burst 16

17. Speed evolution SA-radio and Wind-RAD1:
obtained from the analysis of the radio kilometric Type II burst drift
The shock speed obtained from the analilysis of the radio kilometric Type II burst drift.
Speed in situ obtained for the measuremets in-situ for plasma and magnetic field by STEREO
In soho-lasco liner fit show a acelerations of 9 meter per square second.
We can see as combinations of the difetens measurements show a gradual tendency for the decelerations ot he CME/shock as ir propagates to Astronomic unit 17

18. 3rd case study: 2012/03/05 SOHO-LASCO Position of STEREO
Time Central Angular Vel.
PA Width (km/s)
02:
SOHO-LASCO
Time Central Angular Vel.
PA Width (km/s)
03: 18

19. Dynamic Spectra Central Frequencies
Type II radio burst
Type II radio burst
Type II radio burst
int1 19

20. Speed evolution 20

21. Conclusions
We analyzed a list of Type II radio burst with their corresponding solar association (CMEs and Flares).
From the list, we selected 24 Type II radio bursts observed by the three radio experiments.
We analyzed WIND/WAVES and STEREO/SWAVES radio data associated with CME/shocks. We applied a technique to infer the shock propagation speed at some intervals.
We combined differents observations to infer the evolution speed of CME/shocks. Observations in white-light by SOHO-LASCO and SECCHI-AB, as well as in-situ observations, at diferents times covering different heliocentric distances .
The three events analyzed show a gradual deceleration as they propagate through the heliosphere. 21