Radio Signatures of Coronal Magnetic Fields and Reconnections

1
Radio Signatures of Coronal Magnetic Fields and
Reconnections

• Guang-Li Huang
• Purple Mountain Observatory
• Nanjing, P. R. China

2
Key problems of solar observations in comparison
with models (Forbs, 2004)

• Measurement of coronal magnetic fields - Radio
  diagnosis as one possibility
• Measurement of exact time and location of
  magnetic reconnections Radio Fine Structures as
  the signatures of magnetic reconnections
• Scientific objectives of radio telescopes in near
  future (FASR and etc.)

3
Diagnosis of magnetic fields under Dulk Marshs
approximations (Huang, 2000)
4
Calculation of propagation angles with
polarization degree (Huang et al., 2002)
5
2-D magnetic field with Nobeyama data(Huang et
al., 2002)
6
Calculation of propagation angles with turnover
frequency (Huang et al., 2004)
7
General calculations (Huang, 2004)
8
Calculation with Ramaty and Takakuras model
(Huang et al., 2004)
9
Effects of low energy cutoffs(Huang et al., 2004)
10
Effects of magnetic fields (Huang et al., 2004)
11
Effects of other parameters(Huang et al., 2004)
12
Calculations of nonthermal density (Zhou et al.,
2004)
13
Millisecond radio spikes on Nov 2, 1997(Huang,
2004)
14
17 GHz contours overlaid on SXT and MDI (Huang,
2004)
15
Location of the spike source (Huang, 2004)
16
Radio fine structures - precursors - on Aug 25,
1999 (Huang et al., 2003)
17
17/34 GHz contours overlaid on SXT(Huang et al.,
2003)
18
Location of reconnections ropes (Huang et al.,
2003)
19
New-classical effects in this event(Tan Huang,
2004)
20
Radio ejection accompanied with CME on April 21,
2002 (Huang, 2004)
21
Together with moving type IV(Huang, 2004)
22
Three drift rates current sheet, shock, and
acceleration (Huang, 2004)
23
Evidence of Nobeyama data with CME on Oct 26,
2003 (Ning et al., 2004)
24
Some other works of Chinese solar radio people
using Nobeyama data

• Polarization analysis with NoRH images (Su
  Huang, 2004)
• Spectral index with NoRH and RHESSI (Su Huang,
  2004)
• Complexity of NoRH sources with CMEs (Shao et
  al., 2004, in process)
• Statistics of flare list of NoRH (Tan et al.,
  2004, in process)

25
Summary

• Nobeyama data are necessary for radio diagnosis
  of magnetic fields and reconnections in low
  corona
• Chinese solar radio people pay much attention to
  Nobeyama data due to the same time schedule of
  observations in China and Japan
• Acknowledgement