IPS Workshop 2013 in Nagoya
November 24

Interplanetary Propagation ofCoronal Mass Ejections~Statistical and Case Studies by IPS~
○Tomoya Iju (1), Munetoshi Tokumaru (1),Ken’ichi Fujiki (1), Daikou Shiota(2)(1) Solar Wind Group, Solar-Terrestrial Environment
Laboratory, Nagoya University, Japan.
(2) Integrated Studies Division, Solar-Terrestrial
Environment Laboratory, Nagoya University, Japan.

Introduction

SOHO/LASCO C3(ESA&NASA)

Near-Sun

Near-EarthSpace-borne
Coronagraphin-situobservation?

• A large amount of plasma is expelled from the Sun into theinterplanetary space = Coronal mass ejection (CME).
• Understanding the propagation of CMEs is very important
for the space weather forecast.
• Need more CME observations between 0.2 and 1 AU.

Our Radio Telescopes for IPS Observations↑Solar Wind Imaging Facility↑ Kiso IPS Telescope(SWIFT) [same frequency,[frequency: 327±5MHz,2]2
aperture:≈4000maperture: ≈ 2000 m ]• The g-value is obtained using Kiso IPS Telescope(1997 － 2009) and SWIFT (2010~).

CMEs in the Interplanetary Space• A sky-map of enhanced g-values (b) provides information onthe spatial distribution of CMEs between 0.2 and 1 AU.
• Using SOHO/LASCO, IPS, and in-situ observations, CMEs
are identified in the near-Sun region, interplanetary space,and near-Earth region, respectively.

I. Statistical Study
General Properties of CME propagation

Speed Profiles for 46 CMEs identified by
SOHO/LASCO, IPS, and In-situ Observations
During 1997 － 2011

Fast CMEs [(V − Vbg) > 500 km s−1 ]: 15Moderate CMEs [0 km s−1 ≦ (V − Vbg) ≦500 km s−1] : 25:6
Slow CMEs [ (V − Vbg) < 0 km s−1 ]Kinematics of Fast and Moderate CMEs
• A linear equation(dash-dottedline) is more
appropriate thana quadratic one(broken line) todescribe themotion of fastand moderateCMEs.
a = − γ 1 (V − Vbg )γ 1 = 6.51(± 0.23) × 10 −6 s −1

a = −γ 2 (V − Vbg )V − Vbg

γ 2 = 6.06(± 0.23) × 10 −12 m −1

Kinematics of Slow CMEs
• There is nosignificant
difference
between a linearequation (dashdotted line) anda quadratic one(broken line) for
describing the
motion of slow
CMEs.
a = − γ 1 (V − Vbg )γ 1 = 5.58(± 1.77 ) × 10 −6 s −1

a = −γ 2 (V − Vbg )V − Vbg

γ 2 = 2.36(± 1.03) × 10 −12 m −1

II. Case Study
2-1. Influence of Magnetic field on theInterplanetary Propagation of CMEs
2-2. Evaluation of CME Speed Estimation

2-1. 3-D MHD Simulation for the CME Propagation• Simulation of CMEs with a magnetic tours [Shiota andKataoka, JpGU meeting, PEM05-38, 2013]• Distance：25 Rs ≦ R ≦ 425 Rs (1 AU = 215 Rs)• Consider a dragforce by theinteraction withthe solar wind
and a driving
force by theinternal
magnetic field.
[Shiota and Kataoka, JpGU meeting, 2013]• In this pdf, simulation results areomitted because we will write a paper
for them.

2-2. Comparison between g-map and Vmap: the 28 May 2003 CME

g-value
Velocity(single-station measurement) (multi-station correlation)• We choose radio sources measured both an enhanced
g-value and velocity, and then estimate the CME speed
using them.

2-2. Comparison between two methods ofCME Speed Estimation: the 28 May 2003
CME

848±274 km s−1

641±247 km s−1• CME speeds calculated using data of distance andtime are somewhat larger than those derived frommulti-station correlation.

Summary and Conclusions
I. Statistical Study• We identified 46 CMEs using SOHO/LASCO, IPS, and in-situ
observations during 1997 － 2011.
• For fast and moderate CMEs, a linear equation a = −γ1(V − Vbg)
with γ1 = 6.51 (±0.23) × 10−6 s−1 is more appropriate than aquadratic one to describe their interplanetary propagation.
• For slow CMEs, we need to identify more events and thenexamine their propagation carefully.
II. Case Study• We found from the comparison with a MHD simulation thatthe best-fit parameters (the angular width and strength ofinternal magnetic field) are different for each CME.
• CME speeds calculated using data of distance and time aresomewhat larger than those derived from multi-station
correlation for the 28 May 2003 event.

Calculation of CME
radial speedsdIPS,i, tIPS,i• Reference distances R1,2 andspeeds V1,2
SOHO-IPS: R1 =IPS-ACE: R 2 =1n∑n

1d SOHO + d IPS, ii =12nd IPS, i + d ACE∑ni =12V1 =V2 =1nd IPS, i − d SOHO

∑nti =11n− tSOHOd ACE − d IPS, i∑nti =1IPS, iACE− t IPS, iHere, tSOHO is CME appearance time, dSOHO is Minimum radiusof LASCO C2 F.O.V, P-point distance dIPS and observation timetIPS for a g ≧ 1.5 radio source, tACE is ICME detection time at ACE,and dACE ~ 1AU

Calculation of CME accelerationsFrom speeds v1,2 at reference distances r1,2 , CME appearance
time tSOHO, mean near-Sun CME speed VSOHO, observation
time tIPS for a g≧1.5 radio source, ICME detection time tACE,and mean near-Earth ICME speed VACESOHO-IPS: a1 =IPS-ACE: a1 =1nvIPS, i − VSOHO∑nti =11nIPS, iVACE − vIPS, i∑nti =1− tSOHOACE− t IPS, iHere vIPS, i =v1, i + v2, i2