5月18日 Spectral Lines of Importance for Determining the Magnetic Field of the Active Solar Corona

　　Speaker: Roger Hutton

　　Shanghai EBIT Lab., Fudan University. Shanghai, China

　　Time: 05/18 周五下午2点，器材楼207

　　In this contribution we will present a newly proposed method for a possible measurement of the corona magnetic field strength based on an accidental degeneracy of two quantum states of Fe⁹⁺. This degeneracy is between two quantum states of Fe⁹⁺, namely the ⁴D_7/2 and ⁴D_5/2 of the 3p⁴3d electronic configuration. The 4D7/2 state is forbidden to decay to the ground state whereas the 4D5/2 has an allowed transition. However, the presence of an external magnetic field leads to quantum interference between these two states and opens up an allowed channel for the ⁴D_7/2, we call this a Magnetic Induced Transition, MIT. The rate of MIT transitions depends on the strength of the external magnetic field, hence, a ratio of the transitions from these two ⁴D states can be used as a measure of the field strength.  A very important parameter for this method to work is the closeness, in energy, of the degeneracy of the two states involved. We have measured this for the two ⁴D states in Fe⁹⁺  using the very unique properties of Electron Beam Ion Traps, EBITs. We find the two ⁴D states to be separated by 3.5 cm^-1, which is less than 1/100000 of the ⁴D energy levels above the ground state. We also present a measurement of this fine structure energy based on spectroscopic data from the corona recorded using a spectrometer aboard space-lab.

　　CV of Professor Roger Hutton

　　University Education

　　University of Birmingham, England, 1974-1977, Bsc. in Mathematical Physics

　　Imperial College, University of London, 1977-1978, Msc. in Applied Optics

　　Queen Elizabeth College (London), 1978-1979, London, research student in optics

　　Lunds Universitet, Sweden, 1983-1988, Phd. in Atomic Spectroscopy. Supervisor Professor Indrek Martinson,

　　Postdoctoral Positions.

　　Lawrence Berkeley/Livermore Laboratories, 1988-1990

　　Manne Siegbahn Laboratory, Stockholm, 1990-1991.

　　Academic Positions

　　Researcher, Atomic Spectroscopy, Lunds Universitet, 1991-1994

　　Associate Professor, Atomic Spectroscopy, Lunds Universitet, 1994-2002.

　　Associate Professor, Astronomi, Lunds Universitet, 2002 – 2005

　　Full Professor, Modern Physics Institute, Fudan University, Shanghai, China, 2005 –

　　Publications etc.

　　Over 80 publications in refereed journals covering fields from atomic spectroscopy to collisions of slow and ultra-relativistic particles.

　　Publications, which I have been involved with, have been cited in over 300 papers where I am not an author.

　　Grants etc.

　　Numerous grants from Swedish and EU agencies.

　　2007 Natural Science Foundation of China, X ray detection development, 1.8 million  Chinese Yuen. Also grants for fusion related spectroscopy (nsfc) and detector development in Japan.

　　Administration work.

　　Co-chaired five international workshops in recent years and co-edited proceedings for three of the meetings. Co-editor on a book on the Physics of Highly Charged Ions (Taylor and Fransic 2011). Member of the international organizing committees for the following conferences: Physics of Highly Charged Ions (HCI), Atom Structure and Oscillator Strengths (ASOS) and Physics of Electronic, Atomic and Photonic Collisions (ICPEAC).