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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0261

Formation and oscillation of active region filaments

plan term


@ @


 name : Zhang, Chen @  e-mail : zhangqm[at]pmo.ac.cn

contact person in HINODE team

 name : Shimizu @  e-mail : shimizu[at]solar.isas.jaxa.jp

 abstract of observational proposal
Solar filaments are cold and dense plasmas suspended by the dip-shaped magnetic field lines in the corona. They play an essential role in the large-scale eruptions, such as flares and coronal mass ejections (CMEs) that are the primary factors of the space weather. The formation of filaments has been thought to be due to the condensation of hot plasmas via thermal instability after being evaporated from the chromosphere (Antiochos 1999; Karpen et al. 2005; Xia et al. 2011, 2012; Zhou et al. 2014; Keppens & Xia 2014). The formation processes have a longer timescale (~10 hr) compared with their eruption timescale (~1 hr). However, direct evidence of the prominence formation is rare. Liu et al. (2012) and Berger et al. (2012) discovered the formations of solar prominences using the multiwavelength observations of SDO/AIA. The prominences appeared sequentially from the high-temperature EUV lines to the low-temperature lines around the inferred magnetic dips of the coronal loops.

Filaments are not static anytime. Instead, they keep moving along the magnetic field lines, showing longitudinal oscillations. Jing et al. (2003) discovered (and then Vrsnak et al. 2007 continued to study) the large-amplitude long-term longitudinal filament oscillations using the high-resolution and high-cadence H data from BBSO. The velocity amplitude of the oscillations is 20 – 100 km s-1, the displacement is ~20 – 100 Mm, the period is 40 – 160 min, and the damping timescale of the oscillations is 100 – 600 min (Li & Zhang 2012). Zhang et al. (2012) verified that the longitudinal prominence oscillation can also serve as a precursor for CMEs. Using one-dimensional hydrodynamic numerical simulations, Zhang et al. (2013) carried out in-depth investigations of the triggering mechanism, restoring force, and damping mechanism of the oscillations. The micro-flares or sub-flares near the footpoints of the coronal loops hosting the prominences are demonstrated to be able to trigger longitudinal oscillations sustained by the gravity component along the dipped magnetic field lines. Radiative loss plays a dominant role in attenuating the oscillations.

 request to SOT
7 days ; NFI: Stokes I/V Na 589.6 nm
FOV: 164h~164h, 0.16h/pixel
Cadence: 64 seconds
Telemetry: 255 Mbits/hr, 1530 Mbits/6hr

 request to XRT
Filters: two of the nine filters (Al_mesh, Al_poly, C_poly, Ti_poly, Be_thin, Al_med, Be_med, Al_thick, Be_thick) that are suitable to perform temperature diagnostics using filter-ratio method.
FOV: 384h~384h
Cadence: 1 ; 2 min

 request to EIS
EIS study 251: tr_bright_lo
Slit/slot: 2h
Scan step size (arcsec): 2
Line list:
FeXII 186.88
OV 192.90
FeXII 195.12
HeII 256.32
SiVII 275.35
FeXV 284.16
FeX 257.26
Window width (pixel): 24, 24, 32, 32, 24, 24, 24
Exposure time: 30 seconds

 other participating instruments
1. BFI/TiO
FOV: 70h, pixel size: 0.034h, cadence: 10 s.
2. VIS
FOV: 75h~64h, cadence: 2 s.
FOV: 40h~60h.

We hope to observe active regions not far from the disk center, since we apply coordinated observations of Hinode and BBSO/NST; the latter require sunspots to make the adaptive optics (AO) system work. According to the width of the filament, the EIS No. OF POINTING POSITION can be changed.

Highest priority: to observe newly formed or well-developed active regions.

Second priority: to observe decaying active regions.

Lowest priority: to observe the quiet regions or off-limb regions when active regions are absent.

List of past HOPs in which the present proposer was the PI

HOP0124 (Time-varying Doppler velocity diagnosis of X-ray Bright Points)

Publications out of those HOPs
Zhang, Ping; Fang, Cheng; Zhang, QingMin, gH counterparts of X-ray bright points in the solar atmosphereh, 2012, Science China, Physics (G), Mechanics, & Astronomy, 55, 907

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