1. CME trajectory deduced from cosmic ray measurements K. Munakata, T. Kuwabara and J. W. Bieber

2. Cosmic ray storms isotropic intensity decreases Forbush Decrease anisotropy enhancements B×Gradient anisotropy ⇒ deduction of CME trajectory CME, Shock Geomagnetic & Cosmic-ray storms

3. Ｂ ×Gradient anisotropy ｰ G ⊥ pointing toward CME center : IMF unit vector : density gradient vector : Larmour radius ~0.2 AU for muons

4. CMEs analyzed Data used 35 directions (Nagoya, Hobart, SaoMartinho) 1ry Energy 50~120 GeV Prototype Muon Detector Network Onset time of SSC Max. K p FD sizeCorresponding CME Associated X-ray flare Onset timeSizeLocation 4/11 13:43 8+-2%4/10 05:30X2.3 23  S, 9  W 8/27 19:52 5--2%8/25 16:50X5.3 17  S, 34  E

5. Observation 4/118/27 Gx Gy Gz

6. Method 1 Get r from observed G(r) every hour Method 2 Get trajectory by best-fitting the expected G(r) to the observed Analysis Assume Gaussian CR density distribution, as… : depth: width Then gradient will be… Derive r using observed G(r)

7. G obs |G obs | ⇒ r G obs orientation ⇒ direction of CME center Location of CME center (x,y,z in unit of ) Method 1

8. 4/11 CME by Method1 Moving direction GSE lat.=48°, long.=193° Velocity (using average SW speed 650km/s for Vx…) |V|=1000km/s Width of CME λ=0.10AU Impact parameter at earth D=0.017AU

9. Method 2 Then the gradient at t will be… Set the location of CME center at time t, as… Find parameters which give…

10. Moving direction θ=60°,φ=183° Velocity (Vx=650km/s) V=1300km/s Width of CME λ=0.14AU Impact parameter D=0.035AU 4/11 CME by Method 2

11. Moving direction θ=-12°,φ=212° Velocity (using Vx=500km/s) V=610km/s Width of CME λ=0.087AU Impact parameter D=0.12AU 8/27 CME by Metod 1

12. Moving direction θ= ｰ 10°,φ=224° Velocity (Vx=500km/s ） V=700km/s Width of CME λ=0.14AU Impact parameter D=0.22AU 8/27 CME by Method 2

13. Summary 4/11 CME CME center hit the earth moving northward 8/27 CME CME center passed the south of earth moving from east to west of the sun CME Method1/2 Moving DirectionSpeed [km/s] Width [AU] D [AU] 4/111θ= 48°φ= 193°10000.100.017 2θ= 60°φ= 183°13000.140.035 8/271θ= -12°φ= 212°6100.0870.12 2θ= -10°φ= 224°7000.140.22