ICME in the Solar Wind from STEL IPS Observations Munetoshi Tokumaru (STEL, Japan)

Interplanetary Scintillation (IPS) Measurements as a Useful Tool for the Space Weather Study White Light Image of Solar Corona Sun Earth CME Radio Source Shock Magnetic Cloud (SOHO/LASCO) Coronal Mass Ejection (CME) Interplanetary scintillation (IPS) observations serve as a useful tool to study 3D feature of CME and radial evolution in the solar wind. The utility of IPS observations has been well demonstrated from earlier studies using Cambridge, Pushchino, Ooty, and STEL data.

Projection map of g-values between Interplanetary CME Identified from STEL IPS Observations The g-value represents the relative variation of scintillation level; i.e. solar wind density fluctuations ΔNe (Gapper et al., 1982). STEL IPS observations: Frequency: 327 MHz No. Sources: ~40 sources (ε<90 deg) in a day LASCO(C3) Observations SOHO/LASCO Projection map of g-values between 2000/7/11:22h UT and 7/12:7h UT g>1 → Excess of ΔNe (i.e. Ne) →Interplanetary CME

Retrieval of 3D Structure of Interplanetary CME by Model Fitting Analysis ΔNe Model Observed　g-map Line-of-Sight Sun Earth ΔNe: Density fluctuations K: Normalizing factor w(z): IPS weightening function z: Distance along los q: Spectral index Ψ: Apparent source size λRF: Observing wavelength Search for the best-fit parameters (Cf. Tappin, 1987) Tokumaru, M., et al., AIP Conference Proc. 679, pp. 729-732.

2000 Jul 10 CME Event LASCO Solid line: “Snowplow” model Dash-dot Line: “Aerodynamic Drag” model Parameters: Ambient SW: V=400km/s, N=5/cc (LASCO obs.) Initial Speed =1352 km/s Initial Mass =1.1×1016 g (IPS obs./model fit) Radial thickness=0.16 AU Angular extent/4π=0.17 Models IPS ssc This slide shows variation of CME speeds from the corona to the Earth orbit for a given event. These two lines are model calculations. In these models, the interaction between the solar wind and the CME is a dominant process. In this case, our IPS observations show good agreement with these model calculations, and this is consistent with the shocked plasma hypothesis. IPS observations shows good agreement with model calculations. Radial variation of average speeds IPS obs: ○ Central Axis, ● Earthward

3D Density Reconstruction of IP Disturbances Associated with the 2003 October 28 CME STEL IPS（g-value） Measurements (Left) White-Light Measurements with Solar Mass Ejection Imager (Right) Slower Speed than IP Shock（~1000km/s)　→Internal Part of CME Elongated Structure in NE-SW High-density cloud IPS SMEI (UCSD) Tokumaru et al., J. Geophys. Res., 112, A05106, doi:10.1029/2006JA012043 3D Distribution of Density Enhancements：Yellow dot=Sun、Blue dot=Earth、Solid circle=Earth Ortbit Both data show loop-shaped structure. Tokumaru, M. et al., J. Geophys. Res., 112, A05106, doi:10.1029/2006JA012043

Magnetic Flux Rope Associated with 2003 October 28 CME Cosmic Ray (Muon) Observations (Left) & In situ Measurements by ACE(Right) In situ (ACE) Obs. Cosmic Ray Obs. A: in situ (ACE) IPS IPS lat=46 deg lon=54 deg lat=29 deg lon=75 deg CR B: Kuwabara et al, 2004 C: Kuwabara, 2005 Distribution of IP disturbances observed by IPS and SMEI is in good agreement with the magnetic flux rope. Kuwabara, 2005

Global Feature of CMEs in the Solar Wind Shell-shaped CMEs 1999 Sep 20 event 2000 Jul 10 event 2000 Jun 2 event Loop-shaped Type 1999 Aug 17 event 2000 Jul 14 event 1999 Apr 13 event 2001 Aug 25 event

Origins of Density Enhancement Identified by IPS Compressed Plasma between Shock and Ejecta Prominence Material Contained by a Flux Rope

Sumary 3D distribution of ICMEs has been retreived from IPS observations using the model fitting technique. A variety of global morphology has been revealed from this analysis. 3D IPS reconstructions are useful for studying propagation and origin of ICMEs.

2003 Nov 02 CME Event Solid line: “Snowplow” model (11/2-3) Dashed line: “Snowplow” model (11/3-4) Dash-dot line: “Aerodynamic Drag” model (11/2-3) Dash-dot-dot-dot line: “Aerodynamic Drag” model (11/3-4)