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【期刊论文】NUMERICAL STUDY ON THE EFFECT OF HEAT CONDUCTION ON MAGNETIC RECONNECTION
陈鹏飞, P. F. Chen, C. Fang, Y. H. Tang, and M. D. Ding
Adv. Space Res. Vol. 26, No.3, pp. 525-528, 2000,-0001,():
-1年11月30日
The effect of heat conduction on 2.5D magnetic reconnection, similar to that in Kopp-Pneuman model, is numerically studied. It is shown that the heat conduction accelerates the reconnection, increases the amount of shrinkage of the closed field lines, and increases the average rise speed of the SXR loop. MHD slow shocks contribute to the SXR loop heating. When the timescale of heat conduction is shorter than the Alfv
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【期刊论文】PSEUDO-RECONNECTION IN MHD NUMERICAL SIMULATIONS
陈鹏飞, P. F. CHEN, C. FANG, AND Y. Q. Hu
Chinese Science Bulletin, Vol. 45, pp. 798-801,-0001,():
-1年11月30日
A class of pseudo-reconnection caused by a shifted mesh in MHD simulations is reported. In term of this mesh system, some non-physical results may be obtained in certain circumstances, e.g., magnetic reconnection occurs without resistivity. After comparison, another kind of mesh system is strongly recommended.
MHD,, numerical simulation,, magnetic reconnection
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【期刊论文】FLARING LOOP MOTION AND A UNIFIED MODEL FOR SOLAR FLARES
陈鹏飞, P. F. CHEN, C. FANG, M. D. DING, AND Y. H. TANG
THE ASTROPHYSICAL JOURNAL, 520: 853-858, 1999,-0001,():
-1年11月30日
We performed 2.5-dimensional numerical simulations of magnetic reconnection for several models, some with the reconnection point at a high altitude (the X-type point in magnetic reconnection), and one with the reconnection point at a low altitude. In the high-altitude cases, the bright loop appears to rise for a long time, with its two footpoints separating and the field lines below the bright loop shrinking, which are all typical features of two-ribbon flares. The rise speed of the loop and the separation speed of its footpoints depend strongly on the magnetic field B0, to a medium extent on the density P0, and weakly on the temperature To, the resistivity η, and the length scale L0, by which the size of current sheet and the height of the X-point are both scaled. The strong B0 dependence means that the Lorentz force is the dominant factor; the inertia of the plasma may account for the moderate P0 dependence; and the weak η dependence may imply that "fast reconnection" occurs; the weak L0 dependence implies that the flaring loop motion has geometrical self-similarity. In the low-altitude case, the bright loops cease rising only a short time after the impulsive phase of the reconnection and then become rather stable, which shows a distinct similarity to the compact flares. The results imply that the two types of solar flares, i.e., the two-ribbon flares and the compact ones, might be unified into the same magnetic reconnection model, where the height of the reconnection point leads to the bifurcation.
MHD-methods, numerical-Sun, flares-Sun, magnetic fields
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【期刊论文】A UNIFIED MODEL OF CORONAL MASS EJECTION-RELATED TYPE II RADIO BURSTS
陈鹏飞, Tetsuya Magara, Pengfei Chen, Kazunari Shibata, and Takaaki Yokoyama
The Astrophysical Journal, 538: L175-L178, q 2000.,-0001,():
-1年11月30日
We present a theoretical model for the shock formation that is related to coronal and interplanetary type II radio bursts associated with coronal mass ejections on the basis of the magnetic reconnection model of eruptive solar flares. Coronal type II bursts are usually observed in the metric wavelength range (metric type II bursts), and interplanetary bursts are usually observed in the decametric-hectometric wavelength range (decametrichectometric bursts). Our research shows that the decametric-hectometric type II radio bursts are produced by the piston-driven fast-mode MHD shock that is formed in front of an eruptive plasmoid (a magnetic island in the two-dimensional sense or a magnetic flux rope in the three-dimensional sense), while the metric radio bursts are produced by the reverse fast-mode MHD shock that is formed through the collision of a strong reconnection jet with the bottom of the plasmoid. This reverse shock apparently moves upward as long as the reconnection jet is sufficiently strong and dies away when the energy release of the reconnection stops or weakens significantly. On the other hand, the piston-driven fast shock continues to exist when the plasmoid moves upward. Our model succeeds in explaining the observational result that the piston-driven fast shock that produces decametrichectometric type II bursts moves faster and survives longer than the other shock.
MHD-Sun, corona-Sun, magnetic fields-Sun, radio radiation
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【期刊论文】AN EMERGING FLUX TRIGGER MECHANISM FOR CORONAL MASS EJECTIONS
陈鹏飞, P. F. CHEN, AND K. SHIBATA
THE ASTROPHYSICAL JOURNAL, 545: 524, 2000.,-0001,():
-1年11月30日
Observations indicate that reconnection-favored emerging flux has a strong correlation with coronal mass ejectons (CMEs). Motivated by this observed correlation and based on the flux rope model, an emerging flux trigger mechanism is proposed for the onset of CMEs, using two-dimensional magnetohydrodynamic (MHD) numerical simulations : when such emerging flux emerges within the filament channel, it cancels the magnetic field below the flux rope, leading to the rise of the flux rope (owing to loss of equilibrium) and the formation of a current sheet below it. Similar global restructuring and a resulting rise motion of the flux rope occur also when reconnection-favored emerging flux appears on the outer edge of the
Sun, corona-Sun, flares-magnetic fields-MHD
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