Jet Phenomena in the Solar Atmosphere with Rotational Eruption or Spinning Motion; Observation associated with Our MHD numerical Simulations 2004 年 4 月２１日 宮腰 剛広

Jets associated with Rotating Eruption or Spinning Motion Kurokawa et al. 1987, Solar Phys., 108, 251 Canfield et al. 1996, Apj, 464, 1016 Alexander and Fletcher, 1999, Solar Phys., 190, 167 Pike and MASON, 1998, Solar Phys., 182, 333 Observations

28 May 1998 : two-sided 19 Aug 1998 : one-sided anemone with roration Movie

Anemone type Two-sided Loop Type

19 Aug :50:16 UT NOAA AR8299 at the west limb : one-sided anemone with roration No SXT data (Night) Plasma outflow : lasting 16 minutes, originated in a small loop system Produced another jet some 7 hours Prior to the main jet there is evidence for sporadic ejection of material from the same region Anemone type jets described by Shimojo et al in that the plasma is ejected along a single direction from a basal system of loops

pre Main and post

Pre-jetting phase Loop system (footpoint) exists, bright the throughout event Ten minutes prior to the main phase; blobs ejected along what will be the main Jet cannel; blob ejection interval 2-3 min; distrinctive black and white striations exists

Main: 02:50:25 start; small Ha flare detected at Learmonth Solar Observatory; The main flaring phase is exemplified by a large enhancement; very quickly (within ~2min) a bright arcade is formed; jet traveling at km/s; Alternating dark and white bands, suggesting motion along a twisted structure; This pattern is interrupted the data gap (02:55:20-03:00:18); Main phase

Main phase (continue) When data resumes, a pair of jet is visible; The apparent bifurcation of this jet is interesting (movie shows clearly); The divergence of bifurcation is not constant but changes, suggesting a Dynamic response to the rapid transport of twist (untwisting?) along the field (Canfield et al. 1996), or the development of an instability (such as Kelvin-Helmholtz); Post: jet and anemone disappear,

Yokoyama and Shibata (1995, 1996) Cool and Hot plasma acceleration; Cool; anemone type; cool plasma is ejected along the ambient field by the Sling-shot effect; this may be observed as an Ha surge (Canfield et al. 1996) TRACE 171 and 1216 (contour) 1MK and K The Lya jet is very similar to that observed In the EUV; expelled at the same time; Start off along the same trajectory; An important difference is noticeable, however, The jets are not co-spatial over their entire length. Two jets lie on adjacent fluxtubes and That these fluxtubes diverge at some distance From the original point. This is consistent with model.

28 May :41:58 UT NOAA AR 8227, it was approaching the disk center : two-sided The plasma outflow lasting 16 minutes; Several EUV jets were observed between 27 May 12: May 12:00 From the same region. This jet has the basic structure of the two-sided loop type jets (Shimojo et al. 1996) Away from a central location in two directions, roughly anti-parallel to each other; One direction apparently corresponds to upwards into the oblique open field while the other is in the opposite direction towards the strong magnetic field of the nearby sunspot. Pre-jet phase : 18: :30 Main phase : 18: :57

Pre-phase This pre-jet activity is comprised of at last two small events each displaying The two-sided loop morphology.

The major brightening started around 18:41 and lasting 16 min; Initially we see a small pair of bright EUV loops which extend southwards Towards the sunspot and northwards Towards the ‘open’ field region; The southward jet remains essentially Unchanged throughout the event Suggesting that the jet is being Constrained by the strong field region Of the sunspot. Jet moving at ~250km/s A movie shows the dynamic nature of the activity with the magnetic fluxtubes ‘sloshing’ around as the plasma is ejected, suggesting that as the jet passes The local gas pressure is comparable to the magnetic pressure and the jet can Perturb the field lines

TRACE (18:49:16) and SXT (18:49:07, white contour) (18:44:51, black contour) Both X-ray jet and EUV one are Co-spatial, involving the same set Of nested field lines (if not the same Field lines); An interesting note is the time of maximum Extent of the jet in X-rays precedes that in EUV by 5 min. Delays in the peak emission Of hot and cool plasma are not uncommon (Schmieder et al. 1994) with delays of 3-4 Min. This is similar delay although this Occurs mainly in the outer reaches of the jet. We interpret this as a continuous jet (rather Than a single island) in which the temperature Decreased over time while the velocity remains Fairly constant. In this case, the later phases of EUV emission are enhanced by the cooling of The earlier, hotter jet material.

Discussions The observed intermittent ejection of plasma would represent multiple Tearing? (-  Tanuma) Rotation and untwisting (Shibata and Uchida 1986) One of the characteristics of the Shibata and Uchida model is that the jet consists Of a hot core and cool sheath embedded in a helical magnetic field. This may explain the ‘travel’ pattern observed in the running difference images for The 19 August (figures 2 and 3) both in the pre-flare and post-flare state.

The twist has apparent ‘clearing out’ (03:00:16 UT) as the jet begins to bifurcate. It is unclear how this removal of twist actually progressed, due to a 5-min gap In TRACE data. However, the bifurcation of the jet structure is clearly evident Some 10 min after the flare peak. Bifurcation of plasma jets in astrophysical bodies is not uncommon, although perhaps Rare in the solar case. Ford et al. (1986) observed Ha jet emanating from spiral galaxy NGC 4258, the morphology of which suggests the presence of two double-sided jets which braid around each other before bifurcating at the ends. Such observations are Supported by simulations which demonstrate that bifurcations can result from the nonlinear dependent (cf., Hardee et al. 1995). The observation of the bifurcation of Plasma jets in the solar atmosphere may be a consequence of high spatial and temporal Resolution of TRACE.