1. Group A: S. Bale(Tutor), B. Engavale, W.L. Shi, W.L. Teh, L. Xie, L. Yang, and X.G. Zhang 13,May 2004 3 rd COSPAR Capacity Building Workshop3 rd COSPAR Capacity Building Workshop, Beijing, China Measuring the electric potential at the bow shock Group A: Tutor: S. Bale Crew: L. Xie L. Yang B. Engavale W.-L. Teh W.-L. Shi X.-G. Zhang

2. Group A: S. Bale(Tutor), B. Engavale, W.L. Shi, W.L. Teh, L. Xie, L. Yang, and X.G. Zhang 13,May 2004 3 rd COSPAR Capacity Building Workshop3 rd COSPAR Capacity Building Workshop, Beijing, China Outlines Introduction Data and Analysis Techniques Present result Work to be done

3. Group A: S. Bale(Tutor), B. Engavale, W.L. Shi, W.L. Teh, L. Xie, L. Yang, and X.G. Zhang 13,May 2004 3 rd COSPAR Capacity Building Workshop3 rd COSPAR Capacity Building Workshop, Beijing, China Bow shock  transition region from supersonic upstream flow to subsonic downstream flow.  Density, temperature and fields changes rapidly  Shocks can be found everywhere, near the planets, stars, etc.

4. Group A: S. Bale(Tutor), B. Engavale, W.L. Shi, W.L. Teh, L. Xie, L. Yang, and X.G. Zhang 13,May 2004 3 rd COSPAR Capacity Building Workshop3 rd COSPAR Capacity Building Workshop, Beijing, China Bow shock of Earth magnetosphere return

5. Group A: S. Bale(Tutor), B. Engavale, W.L. Shi, W.L. Teh, L. Xie, L. Yang, and X.G. Zhang 13,May 2004 3 rd COSPAR Capacity Building Workshop3 rd COSPAR Capacity Building Workshop, Beijing, China Solar wind Bow shock Magnetosheath Purpose of our project is to estimate potential energy in the bow shock region.

6. Group A: S. Bale(Tutor), B. Engavale, W.L. Shi, W.L. Teh, L. Xie, L. Yang, and X.G. Zhang 13,May 2004 3 rd COSPAR Capacity Building Workshop3 rd COSPAR Capacity Building Workshop, Beijing, China Energy distribution is earlier studied by J.D. Scudder(1986,1995), but it is not yet understood very clearly. Very few measurements of potential at the bow shock are available. Investigate the role of potential in the energy distribution and its dependence on solar wind properties(M, ,  )

7. Group A: S. Bale(Tutor), B. Engavale, W.L. Shi, W.L. Teh, L. Xie, L. Yang, and X.G. Zhang 13,May 2004 3 rd COSPAR Capacity Building Workshop3 rd COSPAR Capacity Building Workshop, Beijing, China Sharp changing of Variables

8. Group A: S. Bale(Tutor), B. Engavale, W.L. Shi, W.L. Teh, L. Xie, L. Yang, and X.G. Zhang 13,May 2004 3 rd COSPAR Capacity Building Workshop3 rd COSPAR Capacity Building Workshop, Beijing, China Data And Analysis Techniques Data Description FGM 1.Magnetic Fields (FGM) 2.Electric Fields (EFW) 3.Plasma density (CIS) 4.Plasma velocity (CIS)

9. Group A: S. Bale(Tutor), B. Engavale, W.L. Shi, W.L. Teh, L. Xie, L. Yang, and X.G. Zhang 13,May 2004 3 rd COSPAR Capacity Building Workshop3 rd COSPAR Capacity Building Workshop, Beijing, China Analysis Methods 1. Shock identification Some physical quantities, namely, B fields, plasma density, plasma velocity, will change rapidly when traversing the shock. Cluster measures electric fields only in two directions, we want to compute the third component of E field by using this equation.

10. Group A: S. Bale(Tutor), B. Engavale, W.L. Shi, W.L. Teh, L. Xie, L. Yang, and X.G. Zhang 13,May 2004 3 rd COSPAR Capacity Building Workshop3 rd COSPAR Capacity Building Workshop, Beijing, China One crossing of the shock 2001 Mar 31 Assumptions: 1.Quasi-perpendicular shock 2.One-dimensional structure of shock 3.Steady state

11. Group A: S. Bale(Tutor), B. Engavale, W.L. Shi, W.L. Teh, L. Xie, L. Yang, and X.G. Zhang 13,May 2004 3 rd COSPAR Capacity Building Workshop3 rd COSPAR Capacity Building Workshop, Beijing, China 2. Shock Normal Estimate Use crossing times approach to estimate the shock normal in our study. Method description: n v r ij where n=[0.94,-0.2,0.28]

12. Group A: S. Bale(Tutor), B. Engavale, W.L. Shi, W.L. Teh, L. Xie, L. Yang, and X.G. Zhang 13,May 2004 3 rd COSPAR Capacity Building Workshop3 rd COSPAR Capacity Building Workshop, Beijing, China 3. Coordinates transformation Normal Incidence Frame In this frame, the flow will be directed along the shock normal. Maximum variance analysis of electric field (MVAE) denotes the average

13. Group A: S. Bale(Tutor), B. Engavale, W.L. Shi, W.L. Teh, L. Xie, L. Yang, and X.G. Zhang 13,May 2004 3 rd COSPAR Capacity Building Workshop3 rd COSPAR Capacity Building Workshop, Beijing, China 4. Electric potential calculation After transforming the electric fields into the variance space, we integrate the maximum variance of the electric field, which is the normal electric component of the shock, to obtain the electric potential across the shock layer. The estimate of the start time and end time becomes very important in this calculations of electric potential. Vup=670km/s, Vdn=263km/s,  E=1974eV Min Int Max

14. Group A: S. Bale(Tutor), B. Engavale, W.L. Shi, W.L. Teh, L. Xie, L. Yang, and X.G. Zhang 13,May 2004 3 rd COSPAR Capacity Building Workshop3 rd COSPAR Capacity Building Workshop, Beijing, China Present result Analyzed 8 shocks (21 Mar 2001) as a function of Mach number. In order to study this further, we need to study more cases.

15. Group A: S. Bale(Tutor), B. Engavale, W.L. Shi, W.L. Teh, L. Xie, L. Yang, and X.G. Zhang 13,May 2004 3 rd COSPAR Capacity Building Workshop3 rd COSPAR Capacity Building Workshop, Beijing, China Work to be done Cluster data available ⇒ 3 years(2000-2003) ∼ 100 orbits 200 to 2000 shocks By assuming each event analysis take 30 min 6 person (8 hrs/day) ⇒ 1 months back

16. Group A: S. Bale(Tutor), B. Engavale, W.L. Shi, W.L. Teh, L. Xie, L. Yang, and X.G. Zhang 13,May 2004 3 rd COSPAR Capacity Building Workshop3 rd COSPAR Capacity Building Workshop, Beijing, China PROJECT GROUP_ A GROUP_ BGROUP_ CData analysis + programming New interesting results, Need detailed analysis Meeting for the discussion Few months

17. Group A: S. Bale(Tutor), B. Engavale, W.L. Shi, W.L. Teh, L. Xie, L. Yang, and X.G. Zhang 13,May 2004 3 rd COSPAR Capacity Building Workshop3 rd COSPAR Capacity Building Workshop, Beijing, China LOOKING FORWARD FOR THIS PROJECT THANKS FOR YOUR ATTENTIONS !