HOP list   Monthly Events

HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0202

Driving Mechanism of Super-Sonic Flows in the Chromosphere around a Sunspot

plan term


@ @


 name : Katsukawa, Oi, Suematsu, Kusano @  e-mail : yukio.katsukawa[at]nao.ac.jp

contact person in HINODE team

 name : Katsukawa @  e-mail : yukio.katsukawa[at]nao.ac.jp

 abstract of observational proposal
It has been realized that the solar chromosphere often exhibits strong super-sonic flows, especially around a sunspot, driven by magnetic fields, such as strong downflows along a dark filament near its footpoints (Lites 2005, Katsukawa et al. 2010), inverse Evershed flows in a penumbral chromosphere (e.g. Tsiropoula 2000), and penumbral microjets (Katsukawa et al. 2007). It is still poorly known how these flows are driven in the presence of magnetic fields. An important ingredient in acceleration of the flows is strong magnetic and gas pressure gradient. The other possibility is magnetic reconnection, in which magnetic tension force drives Alfvenic flows. It is essential to investigate how the flow velocities are dependent to thermal and magnetic conditions in the chromosphere.

The primary objective of this program is to identify super-sonic flows in the chromosphere around a sunspot, and to investigate how the flow velocities are related with magnetic field configuration and plasma condition. For this purpose, we are going to carry out an observation using Facility Infrared Spectropolarimeter (FIRS) and Interferometric BIdimensional Spectrometer (IBIS) at the Dunn Solar Telescope (DST) of the National Solar Observatory. The observation is expected to provide He I 1083 nm Stokes profiles with FIRS and spectral profiles of the Ca II 854 nm line with IBIS. We would like to propose a Hinode observation coordinated with DST to get information of photospheric magnetic fields at 630 nm and chromospheric activities at BFI Ca II H with SOT. XRT and EIS observations are also requested to get the information of the coronal structures and flows above a sunspot.

 request to SOT
SP: Normal map, 512x512, one side (82" x 82", ~43min)
   -> 290Mbits/map, once or twice per day

FG: BFI/CaIIH+G-band, 1408x1408 2x2 (77" x 77"), 20sec cadence
   -> 340Mbits/hour

 request to XRT
Ti-Poly (or equivalent), 512x512 1x1, 30-60 sec cadence
(dependent on the telemetry allocation)

 request to EIS
YK_AR_50x384 (1" slit, 20sec exp, FOV 50"x384", duration ~20min)
Repeating the study for 2 hrs produces 17Mbits x 6 ~ 100Mbits.

 other participating instruments
Richard B. Dunn Solar Telescope (National Solar Observatory);
FIRS: Spectro-polarimetry in the chromospheric He I 1083 nm
     and photospheric Fe I 630 nm lines.
IBIS: Spectrometry in the chromospheric Ca II 854 nm line.

Time window in day, if required:

<<Minimum duration>>
Minimum duration is two hours depending on the target. The best time window: 15:00 - 17:00 UT (AM in UTC-7 (at Sac Peak))

Desirable duration is about 4 hours (14:00 - 18:00 UT) per one day.

<<Allowability of short interruptions>>
It is preferable that there are no interruptions during the observation everyday.

Target of interest:
We will observe a well developed sunspot far from the limb at the center of our FOV. The target is to be informed every planning periods from the observers (Katsukawa and Oi) at DST.

We will use these observations for Oi's master thesis.

HOP list   Monthly Events