A Plan for Publication of a Magnetic Cloud List

As a Long-Term Database

K. Marubashi1, K.-S. Cho1, K.-C. Coi1,2,J.-H. Baek1, and S.-H. Choi1

1Korea Astron. & Space Sci. Inst. (KASI)2Chungbuk National University

BSS & IHY Workshop, Daejeon, Sept. 2009

Outline of Presentation

1. Introduction Why a new MC list is needed?

2. Some Examples A torus model: Advantages and Necessity

3. Overview of WEB Preparation

4. Summary: Results of a Survey of 1999 Data Comparison with Existing MC Lists

Schematics of Magnetic Cloud

Globally: a loop of a flux rope

Internal Structure: consisting of nested helices with changing pitch angles

Introduction1. Importance of Magnetic Clouds (MCs) (1) Physical links to CMEs (2) Strong Bz to produce geomagnetic storms

2. Problems in Existing MC-Lists (1) Survey is still NOT satisfactory. (2) Some lists contain Non-MC events.

3. Our purpose and Advantage (1) To create the most reliable MC List (2) A torus model: a new tool for identifying MCs

Example 1: An MC explained ONLY by Torus

Magnetic field: rotation > 300°

In Principle, a cylinderModel CANNOT explainsuch large angle rotation.

Example 2: Deviation MC-axis from Filament?

12 May 1977 EruptionMC observed on 16 May (WIND)

NOThis event is referred to in many papers, asevidence for rotationof MC axis during propagation.

However, the MC-axis direction obtained by a torus-model fitting is found to be parallel to the neutral line.(See Next slide)

Our torus fitting gives MC direction consistent with the filament.

WEB Page Outlook

Events (> 7 hours) are listed.

The list consists of yearly table, for the cylinder and torus models, separately.

Result of Surveying 1999 Data

Huttunen et al. (2005): 9 MCs (1 duration < 7hrs, 1 problematic selection)

Lepping et al. (2006): 4 MCs (1 unsuccessful fitting) & 16 MC-like structures (7 MCs from our fitting)

Lynch et al. (2005): 14 MCs (1 problematic selection, 1 unsuccessful fitting, 3 MC-like structures identified to be MCs)

Present Survey: 23 MCs (13 MCs + 4 MC-like + 6 “new”)

Concluding RemarksWe have confirmed the necessity for a new MC list.

(1) The list we are preparing is unique in that fitting results with a torus model are included when necessary.

(2) The WEB page is under construction, the schedule for making public possibly within 2009, at least partly.

(3) It is more advisable to use the list with communication, because further refinement may be needed in some cases, unfortunately.

Thank you very much

foryour

attention!

Super storm of November 20, 2003