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The Halo CMEs’ Speeds and Energy of Their
Related Active Regions
Yang Liu¹, and CDAW Source Identification Team²
¹Stanford University
² Including: E. Cliver, N. Gopalswamy, J. Kasper, N. Nitta,
I. Richardson, B. Thompson, D. Webb, C. Wu, S. Yashiro,
J. Zhang, A. Zhukov, etc.
Motivations
CMEs and active regions (large-scale and local fields):
Observation has shown some CMEs are associated with solar
flares in active regions;
Studies further demonstrate correlation between the soft X-ray
flux of flares and the speeds of the CMEs (Moon et al. 2002;
Zhang et al. 2004); and also show relationship of the inferred
magnetic reconnection rate and the acceleration of the CMEs
(Qiu et al. 2004);
It is generally believed that the energy released during
the events is primarily the free energy stored in the
magnetic field in the corona.
Thus, it is reasonable to search for relationship between
the magnetic energy of active regions and the related
CMEs’ energy.
Purpose of this work
We are seeking for indexes from magnetograms
that can describe the energy of solar active
regions, and also seeking for possible correlation
between the indexes and the related CMEs’
speeds;
We are seeking for advancing our understanding
on underlying link between the local field of
active regions and global phenomenon of
CMEs.
Energy indexes of active regions
From Fisher et al (2000)
Potential field energy of active regions.
Free energy of active regions
Where L is self-inductance
and I is electric current that
(assuming single flux tube). can be computed assuming
E
free _ energy
1 2
LI
2
the field is force free. But we
need to estimate force-free
alpha.
Index of free energy (single flux tube).
twist writhe force free field tilt / length
Two parameters to be calculated:
tilt angle, and force free alpha (alpha).
Samples
We choose events from CDAW (Coordinate
Data Analysis Workshop held in 2005) event list
based on two criteria:
Halo-CMEs;
Solar source is associated with active regions.
ID
Dst
Peaktime
List of the events
CME
Time
Flare
Vel
Ace
Mag
pos
AR
Active region
E
tilt
alpha
flux
netF
len
e32
deg
/pixel
1e21
-1e21
e21
e7 m
8038
0.374
22.4
-0.04
2.10
2.11
-0.14
5.38
8100
5.468
26.3
0.03
11.91
14.73
-2.94
6.18
Yy/mm/dd UT
Yy/mm/dd UT
Km/s
m/s/s
03
97/05/15 1300
97/05/12 0530
0464
-15.0
c1.3
05
97/11/07 0500
97/11/04 0448
785
-22.1
X2.1
09
98/05/04 0600
98/05/02 1406
938
-28.0
X1.1
s15w15
8210
4.434
-154.
0.08?
10.12
13.25
-3.12
2.19
17
98/11/09 1800
98/11/05 2044
1119
-24.0
M8.4
n22w18
8375
4.774
26.5
0.03
14.54
12.88
1.49
5.17
27
00/07/16 0100
00/07/14 1054
1674
-96.0
X5.7
n22w07
9077
5.234
-71.4
-008?
15.04
20.33
-5.48
2.62
29
00/08/12 1000
00/08/09 1630
702
2.8
C2.3
n11w11
9114
3.900
10.6
-0.02
11.76
8.76
3.01
6.17
32
00/10/14 1500
00/10/09 2350
798
-9.8
C6.7
n01w14
9182
1.321
169
-002?
8.94
2.59
6.44
3.21
37
01/03/31 0900
01/03/29 1026
942
3.5
X1.7
n20w19
9393
17.93
-15.8
-0.08
40.27
24.85
15.2
1.94
42
01/09/26 0200
01/09/24 1030
2402
54.1
X2.6
s16e23
9632
4.953
-25.0
0.05
14.15
11.96
2.49
2.51
44
01/10/03 1500
01/09/29 1154
509
-12.0
M1.8
n13e03
9636
3.431
-21.4
0.04
15.71
13.26
2.59
7.07
46
01/10/28 1200
01/10/25 1526
1092
-1.4
X1.3
s18w19
9672
5.318
-155
0.04?
18.65
13.32
5.60
3.78
47
01/11/06 0700
01/11/04 1635
1810
63.4
X1.0
n06w18
9684
5.087
-18.1
-0.03
13.63
13.96
0.629
5.65
48
01/11/24 1700
01/11/22 2330
1437
-12.0
M9.9
s14w36
9704
3.487
-160
0.04
24.91
11.22
13.70
5.71
50
02/04/18 0800
02/04/15 0350
720
2.1
M1.2
s15w01
9906
7.402
-11.6
12.59
18.20
-5.83
6.28
51
02/04/20 0900
02/04/17 0826
1240
-19.8
M2.6
s14w34
9906
6.097
-8.90
13.21
17.21
-4.17
5.06
52
02/05/11 2000
02/05/08 1350
614
78.9
C4.2
s12w07
9934
3.929
-22.7
5.37
9.96
-4.44
4.52
54
02/08/02 0600
02/07/29 1207
562
-4.3
M4.7
s17w14
0039
11.43
-8.56
27.96
33.37
-5.30
1.54
68
03/10/30 2300
03/10/28 1130
2459
-105.
X17
s16e08
0486
18.71
24.6
35.17
33.79
1.42
1.60
69
03/10/30 2300
03/10/29 2054
2029
-146.
x10
s15w02
0486
21.25
35.1
35.96
38.20
-2.23
2.17
70
03/11/20 2000
03/11/18 0850
1660
-3.3
M3.9
n00e18
0501
3.432
28.2
8.68
15.65
-6.98
1.37
76
04/07/27 1400
04/07/25 1454
1333
7.0
M1.1
n04w30
0652
13.81
4.8
24.78
23.80
0.783
6.38
n23w08
Potential field
energy versus
CMEs’
speeds
No correlation
is found.
Properties of active
regions versus
CMEs’ speeds
No correlation was found
between sizes of active
regions and CMEs’
speeds;
No correlation was found
between net flux of
active regions and CMEs’
speeds.
Free energy
in active
regions
versus CMEs’
speeds
Weak correlation
was found
between
E_free/length
and CMEs’ speed.
Energy index
of active
regions versus
CMEs’ speeds
Weak correlation
was found between
the parameter
ε×E_potential and
CMEs’ speed.
Summary
Potential field energy of active regions versus
CMEs’ speed: NO CORRELATION.
Free energy of active regions versus CMEs’
speed: WEAK CORRELATION.
E
free _ energy
1 2
LI
2
Index of free energy of active regions versus
CMEs’ speed: WEAK CORRELATION.
twist writhe force free field tilt / length
Conclusions
We have examined here two measures of free
energy of solar active regions; we found weak
correlations between such measures and related
halo CMEs’ speed;
These correlations imply that, although magnetic
field of active regions is localized and a CME is a
global phenomenon, active regions make a
significant contribution in energizing the active
region-associated CMEs. It suggests again, from
energy perspective of active regions and CMEs,
that local and global fields are coupled each other.
Free energy of active
regions versus
CMEs’ kinetic
energy
No correlation was found
between total free energy
of active regions and
CMEs’ kinetic energy;
No correlation was found
between proxy of total
energy (ε×E_potential) of
active regions and CMEs’
kinetic energy.