1. Investigations of CME in muon flux detected in hodoscopic mode
The International Conference on Particle Physics and Astrophysics
ICPPA
MEPhI, Hotel Milan, 11 October 2016
Investigations of CME in muon flux detected in hodoscopic mode
I.I. Astapov1, N.S. Barbashina1, V.V. Borog1, I.S. Veselovsky1,2,3,
N.V. Osetrova1, A.A. Petrukhin1, V.V. Shutenko1
1 MEPhI; 2 SINP MSU; 3 IKI RAS
Moscow, 2016

2. Muon hodoscope URAGAN
URAGAN (55.7°N, 37.7°E, 173 m above sea level) is the coordinate detector that allows to investigate the variations of the muon flux angular distribution on the Earth’s surface.
URAGAN consists of four independent supermodules (SM), total area ~46 m2. Each SM is assembled of 8 layers of gas-discharge chambers (streamer tubes) equipped with two-coordinate system of external readout strips which provides a high spatial and angular accuracy of muon track detection (correspondingly, 1 cm and 1°) in a wide range of zenith (0°-80°) and azimuthal (0°-360°) angles in the real time mode.
Every minute, angular distribution of muons is recorded in a two-dimensional angular matrix, which represents a muonography of the upper hemisphere with one-minute exposure.

3. Experimental data
To study the URAGAN integral counting rate, 10-min data summed over all modules and corrected for the barometric and temperature effects are used.
Local anisotropy vector
For the study of two-dimensional variations of muon flux registered by the URAGAN, a local anisotropy vector A is used.
Local anisotropy vector indicates the average arrival direction of muons which is close to the vertical.
To study its deviations from the mean value the relative anisotropy vector r and its horizontal projection rh are used:

4. Automatically generated by CACTus using LASCO C2/C3 observations.
Coronal mass ejection
CACTus CME list
Automatically generated by CACTus using
LASCO C2/C3 observations.
Parameters:
# t0: onset time, earliest indication of liftoff
# dt0: duration of liftoff (hours)
# pa: principal angle, counterclockwise from North (degrees)
# da: angular width (degrees),
# v: median velocity (km/s)
# dv: variation (1 sigma) of velocity over the width of the CME
# minv: lowest velocity detected within the CME
# maxv: highest velocity detected within the CME
# halo?: II if da>90, III if da>180, IV if da>270, indicating potential halo/partial halo CME
During the peak of the solar cycle –
more then 100 CMEs/month
During the minimum of the solar cycle –
about 10 – 30 CMEs/month

5. CMEs selection VCME > 500 km/s
From 2008 to 2015 was 2237 CMEs with the velocity more than 500 km/s
Dt0_CME - the difference between the start one of CME and the next CME
If Dt0_CME < 24 hour, then the events are combined into a group

6. Summary data for calculating the speed and the start group time
By number of CME in group to the event are divided into:
Single CME
Weak group (2 – 4 CME)
Average group(5-10 CME)
Powerful group (> 10 CME)

7. Example response

8. Results
Powerful group
Average group
Weak group
Single CMEs

9. The density distribution in interplanetary space
iNTEGRATED SPACE WEATHER ANALYSIS SYSTEM (iSWA)
The density distribution
in interplanetary space
The velocity distribution
in interplanetary space

10. Is this CME geoeffective?
OMNI data:
The time Δt during which the CME passes a distance of 2 a.u. was estimated for each event. Then, according to the OMNI data the average values of the magnetic field B, solar wind velocity V and Kp-index in the time interval t0+Δt (t0 – time of the CME beginning according to the CACTus (COR2 STEREO-A data) were calculated. The obtained values of <B> and <Vsw> considering their spread do not exceed the average values calculated for the period of observations of the interplanetary magnetic field and solar wind from 2005 to Kp – index did not exceed 4 for all events.

11. «Geoeffective» CME CACTus: LASCO: STEREO-B: 2014/09/10 18:48
V ~ 1100 км/s
2 а.u. ~ 3 days
iSWA:

12. 2014/09/10
OMNI data:
URAGAN:
AFD ~ 1.5 %:

13. «Non-geoeffective» CME
CACTus:
LASCO:
STEREO
2015/03/10 3:36
V ~ 760 km/s
2 a.u. ~ 4,5 days
iSWA:

14. 2015/03/10
OMNI data:
URAGAN:

15. No
CME
beginning t0
<VCME>,
km/s
Time of passage 2a.u., days
<B>, nT
sB, nT
<Vsw>, km/s
ssw, Kp
GEO?
Response rh
URG FD,% 1
:24
1135
3.1
6.26
2.24
561 31 4
GEO +
1.2 2
:48
287
12.1
7.19
3.10
378 38
1.5 3
:24
315
11.0
7.93
3.21
480 66
:25
504
6.9
3.99
1.61
376 34
NON-GEO 5
:55
1840
1.9
5.05
0.51
388 14 6
:09
885
3.9
7.53
2.03
505 80 7
:09
1531
2.3
4.82
1.42
508 58 8
:36
503
5.51
1.73
365 16 9
:12
498
7.0
4.83
1.70
302 19 10
:00
419
8.3
5.10
1.02
389 25 11
:00
637
5.5
12.12
8.18
492
116 12
:12
675
5.1
4.23
1.01
462 35 13
:27
726
4.8
7.64
2.45
358 23
2.1
:36
1126
6.30
0.37
420 17 15
:03
512
6.8
5.77
355 24
:00
879
4.0
6.31
0.79
406
:40
722
1.15
510 49 18
:48
946
3.7
7.45
5.40 62
:00
502
8.21
5.57
360 26 20
:48
422
8.2
5.54
1.81
481 69 21
:12
520
6.7
4.45
1.46
313 22
:48
1213
2.9
9.99
8.14
383
111
2.7
:36
644
5.4
5.7
2.05
554 83
:09
591
5.8
6.40
2.53
326 39
1.1
:12
459
7.5
6.81
2.93
429 61
1.3
:24
466
7.4
9.90
4.68
536 57
A total of 26 coronal mass ejections was considered that occurred in 2014 and 2015, were identified as non-geoeffective 14 of them.
Of the 14 non-geoeffective CMEs in 6 cases was showed in response to the anisotropy of the muon flux according URAGAN data, while changes in the counting rates was not observed during such events.
During geoeffective CMEs usually observed Forbush decrease. In this case, 9 events from 12 events observed changes in the values of the local anisotropy muon flux.

16. Conclusion
Registration of muons in the hodoscopic mode enables to investigate with a single setup not only the intensity of the cosmic ray flux, but also its local anisotropy sensitive to the changes in the heliosphere.
Non-geoeffective ejections have a small effect on the response muon hodoscope.
The presented approach to the study of coronal emission mass will be the basis of the method identification of geoeffective events.
This work was performed at the Unique Scientific Facility “Experimental complex NEVOD” in Moscow Engineering Physics Institute

17. Thank you for you attention