Radio Observations of Solar Eruptions

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Radio Observations of Solar Eruptions

• N. Gopalswamy
• NASA/GSFC Greenbelt MD USA
• Solar Physics with the Nobeyama Radioheliograph
• Nobeyama Symposium Kiyosato Oct 26-29 2004

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Thanks to

• Y. Hanaoka
• M. Shimojo
• K. Shibasaki
• H. Nakajima
• T. Kosugi
• S. Enome
• Nobeyama staff who pleasantly provided all
  necessary support

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Sun in Microwaves

• Quiet Solar disk at 10,000 K (most pixels are at
  this temperature) QS
• Small bright areas on the disk active regions
  (AR), post-eruption arcades (AF)
• Dark areas on the disk Filaments (F) because Tb
  8000K
• Bright regions outside the disk Prominences (P)
  Tb 8000 Kgtgt optically thin corona (200 K)
  Sometimes mounds consisting of AR loops (Tb gt
  10000K)
• Dimming (deficit of free-free emission) can be
  observed in some limb events.
• Prominences and filaments erupt as part of
  coronal mass ejections
• 100s of eruptions documented on the NoRH web site
• Selected references Hanaoka et al., 1994
  Gopalswamy et al., 1996 1999 2003 Hori et al.
  2000 2002 Kundu et al. 2004

P
F
AF
F
AR
QS
tff 0.2?f--2T-3/2n2dl gt1 for n1011 cm-3 T8000
K, f17 GHz and L gt1 km ? Tb T
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Eruptions

• Prominence/filament eruptions
• (Jets) Kundu, Shimojo
• (Blobs) Hori, Shibasaki
• (Waves) White, Aurass
• (Radio bursts) G. Huang
• Slow Eruptions
• Fast eruptions
• CME-PE statistics
• Implications to polarity reversal GCR
  modulation

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Prominence Eruption
1992 Jul 31 Hanaoka et al.1994
P
CME
SXT/AF
- Post-eruption arcade in microwaves -
Prominence, Post-eruption Arcade Consistent with
Standard Eruption model (Carmichael (1964),
Sturrock (1968), Hirayama (1974), Kopp and
Pneuman(1976) CSHKP) - No CME observations, but
SXR Dimming Signature
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Three-Part CME
Gopalswamy et al, 1996, 1997
P
16 km/s
12 km/s
AF
4 km/s
Jul 10-11, 93

• - All features of a typical CME in X-rays and
• Microwaves
• Kinetic energy (5.1026 ) lt thermal energy
  (6.1028)
• Low-end CME
• Helical motion of the prominence followed by
• radial eruption
• Recent examples of helical motion by Hori (2000)

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Filament Eruption and Dimming
Gopalswamy and Hanaoka, 1998
Final 68 km/s Accel 11ms-2
0120
0641
AF
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Filament is CME CORE
Direct comparison with CMEs became possible when
SOHO data started pouring in
MLSO He 10830 images
Gopalswamy, 1999
Additional Core
He10830 filament at1754 UT slowly rises and
reaches the limb by 0003 UT (2/7) ? tracked in
microwaves as a prominence ? becomes the CME
core in white light
Gopalswamy et al .98 GRL
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Post-eruption Arcade
Yohkoh/SXT images showing the formation of a
post-eruption arcade, which lasts for a day
SXR Arcade after eruption larger volume involved
than Indicated by filament 1-AU Magnetic Cloud
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A Complex Filament Eruption
LWS CDAW 2002 (Shimojo), Kundu et al. 2004 See
also Hanaoka Shinkawa, 1999 on covering of
bright plage by erupted filament
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Two CMEs?
Kundu et al. 2004
7.25 Ro/hr Onset 0449 Corrected445
650km/s
50km/s
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CME Collision A slow CME is Deflected by a Fast
one

• Slow CME (290 km/s) overtaken by a fast CME (660
  km/s)
• The slow CME core deflected to the left from its
  trajectory

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Acceleration likely caused by the impact of fast
second CME
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Microwave Observations of CME Initiation
A very fast CME 5 Rs in less than 30 min ? gt
2000 km/s
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An Eruption viewed in microwaves
Gopalswamy, Shimojo, Shibasaki, 2004
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Microwave Emission seems to be from the body of
the CME
0217 0216
0217 0213
17 GHz
17 GHz
1635 km/s
C2
C3 0242
C2 0230
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An Eruption viewed in microwaves
0215 UT
HXR 930 km/s Hudson et al. 2001
Nobeyama HXT Catalog
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Microwave Source Evolution
HXR
Hudson et al 2001
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Similar to Moving type IV?
1600 km/s
2465 km/s
C2
17 GHz 1925 km/s
73.8 MHz
1635 km/s
Gopalswamy Kundu 1992
- The Microwave Structure is either the CME
itself or a substructure, but not the core. -
Microwave spectrum (17 and 34 GHz) indicates
nonthermal emission - Similar to moving type IV
burst
C3
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CMEs Prominence Eruptions (PEs) Statistical
Studies

• Most studies started with CMEs and found PEs to
  be the most common near-surface activity (Webb
  et al., 1976 Munro et al. 1979)
• Reverse studies were rare. Hori et al. studied 50
  NoRH PEs (2/1999-5/2000) and found a 92
  association. (They required simultaneous
  availability of SOHO, Nobeyama and Yohkoh data)
• A comprehensive study using all the PEs (226)
  detected automatically showed that 72 of all PEs
  were associated with CMEs (Gopalswamy et al.
  2003a 2004)

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Height-Time Plots of All PEs
Gopalswamy et al. 2003

• The height-time plots can be broadly classified
  as radial (R 82) and Transverse (T 18)
• R events reached larger height (1.4Rs) compared
  to T events (1.19Rs)
• Most R events (83) were associated with CMEs
  most T events (77) were not.
• 134/186 (72) PEs had CMEs 42 (22) had no CMEs
  11 (6) had streamer changes
• The majority of Streamer change events were T
  events the rest were low-height R events

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Properties of Prominence Eruptions (PEs) with
and without CMEsnon-CME PEs are slower, have
mostly transverse trajectories, and the maximum
height reached is rather small
1.20 Ro
Without CMEs
22 km/s
Without CMEs
68 km/s
With CMEs
With CMEs
1.40 Ro
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2001/08/29 Event no CME
17 GHz Nobeyama
LASCO
LASCO/C2 images show no changes around the Time
of Prominence Eruption
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Streamer Change
Most of these streamers Disrupted within a day.
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Temporal Relationship of PEs and CMEs

• The onset time differences close to zero.
• CME onset times extrapolated to 1 Rs from
  extrapolating linear h-t plots

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PE-CME Spatial Relationship
Open circles ? PEs during SOHO downtimes

• Strong evidence for PE-CME association
• Previously shown by Hundhausen (1993) for SMM CMEs

During Solar Minima the global dipolar field is
strong and guides eruptions
PE
CME
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Non-radial motion

• Prominence Eruption in the SE direction
• Corresponding changes in the streamer
• CME Core position angle 90 deg
• Influence of the global field
• Gopalswamy, Hanaoka, Hudson 1999
• Filippov, Gopalswamy, Lozhechkin, 2001

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CMEs Prominences

• High latitude (HL) prominence eruptions and CMEs
  during CR 1950-1990 (mid 99 early 02)
• N-S asymmetry (NHL ends in 11/00 SHL ends in
  5/02)
• These CMEs are not associated with sunspot
  activity

Gelfreikh et al 2002
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N

PCF
- - - -

W
E
- - - -

- - - -
S
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Cycle 23
Arrows Lorenc et al. 2003 Harvey Recely,
2003 Gopalswamy et al., 2003

• HL Rate picks up when polar B declines
• North polar reversal at the time of cessation of
  NHL CMEs
• South polar reversal 1.5 yr later, again
  coinciding with the cessation of SHL CMEs
• LL CME rate rather flat after a step-like
  increase
• Consistent with the time of PCF disappearance

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Cycle 21

• Solwind coronagraph on board P78-1 (corrected
  rates published by Cliver et al., 1994)
• PCF Webb et al. 1984 Lorenc et al. 2003
• KPNO mag data
• CME cessation coincides with the polarity
  reversal

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CMEs and GCR Modulation
Gopalswamy 2004
Gopalswamy 2004
Alt0
Agt0
Agt0
HL
NoRH PE
LL
Lara et al. 2004
Moraal, 1993
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Concluding Remarks

• NoRH has contributed profoundly to the study of
  CMEs by providing info on various aspects CME
  initiation/acceleration, Post-eruption arcade,
  CME relation to global B
• Clarified CME-PE relationship unambiguously
• Contributed to the understanding of Polarity
  reversal and high-latitude Eruptions
• Prom eruptions have implications to Sun-Earth
  connection as well as Sun-GCR connection
• It will be great if NoRH can see a 22-yr cosmic
  ray modulation cycle

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Polarity Reversal in Photospheric Field
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When are the reversals?

• HL streamer peak (Feb 2000) implies presence of
  HL closed structures. ? reversal is not complete
• HL streamer brightness declines significantly
  towards the end of 2000 agrees with CME
  cessation

Wang, Sheeley Andrews, 2002
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A High-latitude CME PCF
Nobeyama Radio Prominence
LASCO/C2
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Emission Mechanisms(n, T, B, Fnt)

• Thermal Emission
• - Free-free (8000 K to 10 MK)
• - Gyroresonance (Active Regions)
• Nonthermal
• Gyrosynchrotron (incoherent)
• - Plasma emission (nonthermal electrons ? plasma
  waves ? radio emission at fp, 2fp)
• Other coherent processes