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Correlation between halo coronal mass ejections and solar surface activity (G.Zhou et al. 2003)

Correlation between halo coronal mass ejections and solar surface activity (G.Zhou et al. 2003). Three-dimensional flux rope model for coronal mass ejections based on a loss of equilibrium (Roussev et al. 2003). （時間があったら）簡単に研究紹介. 太陽雑誌会　（５月１２日）　　宮腰剛広. Introduction.

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Correlation between halo coronal mass ejections and solar surface activity (G.Zhou et al. 2003)

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  1. Correlation between halo coronal mass ejections • and solar surface activity(G.Zhou et al. 2003) • Three-dimensional flux rope model for coronal mass • ejections based on a loss of equilibrium (Roussev et • al. 2003) • （時間があったら）簡単に研究紹介 太陽雑誌会　（５月１２日）　　宮腰剛広

  2. Introduction • Statistical Study of the relation between • halo coronal mass ejections and solar surface • activity • With LASCO & EIT (main) • Goes, MDI, BBSO, SXT, and etc. (sub) • The events of 1997 – 2001

  3. Sampling the frontside CMEs (1) • after March 1997 to 2001 • Firstly, we obtain all the halo CMEs whose angular • widths are greater than 130 degree. We find 519 such • halo CMEs. • Secondary, with EIT movies and EIT running difference • (RD) movies to check whether these halo CMEs have • counterparts on the visible solar disk. Here two criteria • are used to identify frontside halo CMEs. 1. the surface activity starts in the time window TM-30 --- TM+30 min 2. the position of solar surface activity (with EIT) is under the span of the associating CME

  4. Sampling the frontside CMEs (2) PSSA If a CME's SRPA is within the range of the CME's span, the second criterion is satisfied. • If a CME is associated with such surface activity which • satisfies the above two criteria, we identify the CME as • frontside one. 197 events

  5. Grouping the surface activity(1) • we only take two primary forms of solar activity, the • flares and filament eruptions, into account about Flares • To identify associated flares, (with EIT & SPIDR) • If a flare seen in EIT images takes place within the • duration of a X-ray burst and their position difference • is within the range of -5 --- +5 degree in both the latitude • and longitude, we regard the two sets of observations • as the same event • With regard to the events not listed in X-ray flare • categories, If (increased intensity / background • intensity) > 50%, we classify it as a flare

  6. Grouping the surface activity(2) about Filament Eruptions • We adopt two criteria in identifying a filament eruption. 1. dark and/or bright plasma ejecta, which is an empirical criterion proposed by Subramanian & Dere (2001) 2. appearance of two flaring ribbons and post-flare loops, which is suggested by this paper. • we only group the solar surface activity into the • following three categories: A(a)-Flares with obvious filament eruptions A(b)-Flares which may have been preceded by filament eruptions but cannot be confirmed by the available data base; B-Filament eruptions with too little brightening to be termed flares.

  7. Grouping the surface activity(3) • about symmetry, If the difference between SRPA and CPA or PA (to 360 degree halo CMEs) of a CME is not greater than 20, we define the event as symmetric, or else it is asymmetric.

  8. Example (1) 2001 Jan 20 CME A typical example of A(a) • start time: near 18:36 UT • average speed : 839 km/s • Fig 2B : BBSO H-alpha • a filament lay in the AR9313 • at 08:04 UT before the initial • CME time • Fig 2C : MDI • Fig 2DEF : EIT (M1.2 flare) D) bright and dark ejecta E) two ribbons F) post flare loops  this is eruptive flare • PA --- 64 deg, SRPA --- 100 deg, •  asymmetric event

  9. Example (2) 2001 Apr 6 CME A typical example of A(b) • start time: near 18:54 UT • average speed : 1270 km/s • Fig 3C : H-alpha • filament exists • Fig 3DEF : EIT (X5.6 flare) E) running difference  propagating dimming • we cannot ascertain whether the • filament erupted • PA --- 147 deg, SRPA --- 115 deg, •  asymmetric event

  10. Example (3) 2000 May 8 CME A typical example of B • start time: near 12:48 UT • average speed : 465 km/s • Fig 4B : BBSO H-alpha • Fig 4C : MDI • Fig 4DEF : EIT • development of filament eruption • no corresponding Goes X-ray flare • CPA --- 216 deg, SRPA --- 210 deg, •  symmetric event

  11. Statistical results(1) • Table 2 • Most of these events except for 32 events in Category A(a) • and A(b) have flare records in GOES X ray. • Those 32 events whose intensity increase are greater than • 50%, as defined in Sect. 2.3, were also regarded as flare • events. • Filament eruption : EIT, BBSO, HAFB, HSOS, etc. • at least 94.4% are associated with filament eruption

  12. Statistical results(2) • Table 3 • The other 322 CMEs are not all from the backside. There are two reasons for us to exclude these 322 CMEs. 1.Some CMEs with high cadence EIT data are excluded because no associated activity was observed on the visible disk. Those CMEs may not include frontside ones, 2.the others with low cadence or no EIT data that are excluded may include some frontside ones. only two conditions exist, frontside and backside, thus half of the CME events should belong to the frontside, that is to say, 259 CMEs are possible. We find 76% (197/259) CMEs to be associated with surface activity, which is higher than that of most previous statistical results. • among 141 CMEs associated with GOES X-ray flares, 83 CME • initiations are seen to precede flare onset, while the other 58 are • the opposite

  13. Concluding remarks • 173(88%) associated with flares, 187(94%) with filament • eruptions • 79% whose source regions are inside active regions, 21% • outside • about 50 % symmetric

  14. Three-dimensional flux rope model for coronal • mass ejectionsbased on a loss of equilibrium • (Roussev et al. 2003) The model of the Titov & Demoulin (1999) • two point magnetic charges buried at a • depth z = -d below the surface and • 　ｌocated at x = ±L. • long line current, I0, that coincides with • the x-axis and also lies below the • photosphere at depth d • unstable if the largeradius, R, of theflux • rope exceeds root 2L,where L is halfthe • distance between thebackground • sources ±q. • force-free limit, gas is hydrostatic • (photosphere – transition – corona) • ideal MHD, BATS-R-US method, • with AMR (about 7M mesh) • boundary: highly conducting (z=0) • outflow side (x,y) • open (z=zmax) initial condition color : magnetic fields intensity

  15. Fig.2 The velocity of the O-point is decelerated (not escape case) Fig.3 t=35 min. (isosurface shows current density) magnetic fields exists outerby I, so the flux rope cannnot escape but stop The most plausible explanation of this structure is that there is an interchange reconnection between the highly twisted field lines of the flux rope and the overlying closed field lines from the ±q sources. As a result of this process, the newly created closed field lines connect the two flux regions. about 17% of magnetic energy is converted into thermal and kinetic energy (t=19)

  16. これから花山でやりたいと思っていること • 理論、数値シミュレーション リコネクション（田沼） CME(Chen  　　　　塩田、宮腰、、、） 活動域構造、 ジェット　（宮腰） 対流層磁場（磯部） 個々のオブジェクトについて理解を深化させるとともに、 各現象間のつながりを、数値シミュレーションを武器に、理論的に 明らかにする （ダイナモ) → 対流層　→　光球彩層、黒点　→　活動域コロナ　 →　磁気エネルギー解放 →　太陽面爆発現象　 →　大規模磁場構造へ影響　→　CME　→　宇宙天気予報　 （マンパワー、技術力、利用可能な計算機資源、等の総合力において、 　我々のグループは世界でもトップ集団の中にいるのでは？）

  17. これから花山でやりたいと思っていること • データ解析 １９９２年９月６日　（NOAA　７２７０）　のフレアの解析 ようこう　＋　飛騨DST （宮腰、田沼、成影、柴田、..........) 次の学会での口頭発表を目標に

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