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Solar Group

Department of Physics

University of Wales, Aberystwyth

Aberystwyth

Ceredigion

SY23 3BZ

UK

Tel:  +44 (0)1970-621542

Fax: +44 (0)1970-622826

 

 

Project Scientist

 Dr. Xing Li        

 

Research Staff

Dr. Nicolas Labrosse        Dr. Bo Li

 

Postgraduate Students

    Huw Morgan       Ian O'Neill

 

Support Staff

Dr. Tarlochan Virdi (Computer Facilities Manager)

 

 

 

Dr Xing Li (xxl@aber.ac.uk) +44 (0)1970 621542 [top]

 

Research Interests:

Coronal heating has been a myth for several decades. The temperature of solar atmosphere at the photo sphere is about only 5000 degrees. However, they reach about 1 million degree in less than 20000 km above the photosphere. What physical processes are responsible for such a heating? My main research interest is the coronal heating and solar wind acceleration. For this purpose, multi-fluid solar wind modeling is the one of the key tools to understand physical processes in the corona and interplanetary space. One of my major scientific contributions is to find that oxygen ions are not only much faster than protons in the inner corona, and they have a large temperature anisotropy as well. This discovery greatly changes our view of the coronal heating and solar wind acceleration mechanism. Now the preferential acceleration of minor ions in the solar wind is now a well-known fact, even though it is quite counterintuitive. Special attention is paid to the role of ion cyclotron resonance and electromagnetic instabilities in regulating the acceleration and thermal anisotropies of the solar wind ions. I developed a 16-moment solar wind model to study the anisotropy of protons in the fast solar wind.

New!!! Exciting results from our hybrid simulation: Resonant interaction between cyclotron waves and ions in the solar wind. Check to view the movie below. Paper has been submitted to Journal of Geophysical Research (by X. Li and S.R. Habbal)..

1. Evolution of velocity distribution functions of oxygen ions(8.8M).  

2. Evolution of velocity distribution functions of protons(6.8M).

 

We are actively working on the thermal equilibrium of transition region ions and characteristics of the spectral lines of those species. An improved understanding of these ions may be a key for us to unlock the secrets of the corona heating myth.

A coronal funnel heating by ion cyclotron waves. It is shown that alpha particles are preferentially heated. As a result alpha aprticles are hotter and faster than protons. For Astrophys. Journal Letters, 571, L67, 2002.

Further information is available here

 

 

Dr Nicolas Labrosse, (nll@aber.ac.uk)

 

 

Bo  Li (bbl@aber.ac.uk) +44 (0)1970 622821 [top]

 

2D numerical modeling of the corona expansion and the solar wind acceleration. I am currently working on the 2D structures of the solar wind species temperature anisotropies. 

 

 

 

 

Huw Morgan (hhm01@aber.ac.uk) +44 (0)1970 622821 [top]

 

I'm a 1st year PhD student and my main research topic is making connections between the sun and the solar wind. My current work deals mainly with satellite spectroscopic observations of oxygen and hydrogen lines in the corona, which we can use to estimate temperatures, densities and outflow velocities as well as detecting structures such as streamers. 

 

Ian O'Neill (ijo98@aber.ac.uk)

 

I am currently looking into theoretical modelling of the Solar corona by modifying existing codes and investigating the plasma parameters which combine to produce the heating and acceleration of the Solar Wind. There is a focus on plasma wave dissipation (i.e. ion cyclotron waves interacting with Solar Wind particles), but there must be an awareness of other phenomena that may be contributing to the observed heating. I will also be comparing data from the instruments onboard the SoHO and Ulysses missions with existing models to create a more accurate understanding of the nature of space plasma in these extreme conditions.

 

 Further information is available here

 

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Copyright 2002 The Department of Physics, University of Wales, Aberystwyth, UK. 

Pages maintained by X. Li

Email xxl@aber.ac.uk

Tel    01970 621542

Fax   01970 622826