Download presentation
Presentation is loading. Please wait.
1
Synoptic maps and applications Yan Li Space Sciences Laboratory University of California, Berkeley, CA HMI team meeting, Jan 27, 2005, Stanford
4
Synoptic frame
5
Basics of the PFSS Model Useful attributes of the model include open/closed field regions (e.g. coronal hole footprints for a specific photospheric field description). The last closed field lines form the helmet streamer belt whose cusps at the source surface define the base of the heliospheric current sheet. (Y. Li) Source Surface
6
PFSS model gives: Coronal holes Coronal field lines Source surface neutral lines http://sprg.ssl.berkeley.edu/mf_evol/
7
MDIWSO MWONSO
12
Li et al., 2001 Newly opening field lines
13
This long term record of longitudinally averaged synoptic maps from the MWO magnetograph shows the relative phasing of the solar polar field reversal and the active region polarity reversal (Hale cycle). This has important implications for the likely CME initiation process
14
Luhmann et al., JGR, 2002 Solar cycle variation of solarwind source, color-coded by photospheric magnetic field polarity. Red designates radially outward fields, and blue designates radially inward fields.
15
Luhmann et al., JGR, 2002 Solar cycle changes of Solarwind source at the photosphere. Photospheric field strength at the foot points are color coded. Red designates strengths >30 G, blue designates strengths <10 G, and green denotes intermediate values.
16
Luhmann et al., JGR, 2002 Solar cycle variation of solar wind velocity inferred using the Wang- Sheeley-Arge model. Red designates inferred speeds >550 km/s, blue designates inferred speeds <350 km/s, and green denotes intermediate values.
17
U of Colorado and UCB (Arge et al., JASTP, 2004) Solar Event: May 12, 1997 Solar Wind and Stream Context Derived Coronal Holes and Photospheric Field Polarity Solar Wind Speed at Source Surface (2.5Rs) Solar Wind Speed Predictions & Observations Predictions Observations IMF Polarity Predictions & Observations Stream source region May 12 th CME (suggests solar wind stream following the ICME comes from the southern hemisphere)
18
To study coronal field configuration and topology of CME cases.
26
To study field line connections among active regions.
27
A simple loop on Dec. 26, 97.
28
Complex loops, named x-loops, on Sept 9, 1998. PFSS lines compare well with sxt loops.
29
Longterm behaviour of TLSs Ten years of data from 1992 to 2002 are combined to give the display. Top: green shows the points where the magnetic field strength is above 50G, and where we start to trace field lines. Middle: red shows the closed field lines starting from the strong field regions, our proxy for TLSs, which to some extent take on the solar cycle butterfly trend. Bottom: red shows a subset of closed field lines that both ends are in strong field regions. Solar Minimum Maximum
30
To be the initial condition for MHD global models.
31
CR1935 ZUES coronal (from S. Ledvina, SSL/UCB)
32
Problems encountered Data gaps, Polar regions, Resolution, Cadence, Noise.
Similar presentations
© 2024 SlidePlayer.com. Inc.
All rights reserved.