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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0129

CORE: ToO: Survey of Active Region Phenomena Associated with Micro-Type III Bursts

plan term


@ @


 name : Masuda @  e-mail : masuda[at]stelab.nagoya-u.ac.jp

contact person in HINODE team

 name : Masuda @  e-mail : masuda[at]stelab.nagoya-u.ac.jp

 abstract of observational proposal
To observe the evolution of active regions associated with micro-type III radio bursts.

Scientific Background:
Micro-type III radio bursts, reported by Morioka et al. (2007), are the elements of the type III storm, characterized by (1) a very low intensity, (2) short durations, and (3) continuous emissions compared to the ordinary type III radio bursts. The micro-type III bursts are not necessarily accompanied by energetic phenomena like flares, different from the ordinary type III bursts. The existence of micro-type III bursts suggests that a very small fraction of electrons are continuously accelerated/heated, and escape from the Sun toward the interplanetary space. Morioka et al. found that the micro-type III bursts are generated from the active regions bordering on coronal holes. The interaction between active regions and coronal holes may be a key to accelerate the beam electrons that produce the micro-type III radio emissions. Therefore, the micro-type III burst would be a diagnostic phenomenon that indicates the existence of field-aligned electron acceleration in active regions.
Recently, Minoshima et al. performed a drift kinetic Vlasov simulation of solar flares to understand the flare particle acceleration and transport mechanisms. From the numerical simulation, they propose a scenario for the creation of escaping electrons by a centrifugal acceleration taking place in curved open magnetic field lines. The mechanism requires only the bulk motion of curved magnetic field lines, not explosive phenomena such as magnetic reconnection. This mechanism most effectively works at the boundary between open and close field lines. In these two viewpoints, Minoshima et al. suggest this mechanism as a plausible candidate of the acceleration process of electrons for micro-type III bursts.
For further understanding of the micro-type III bursts, the evolution of the burst-generating active regions should be observed in a high time resolution (<~10 s), which has not been implemented so far. The evolution of magnetic field lines at the boundaries between active regions and coronal holes is particularly interesting.
Currently, several spacecraft such as Geotail, Wind, and STEREO continuously monitor solar radio waves at the MH/HF frequency range. Moreover, Iitate Planetary radio telescope (IPRT) of Tohoku University observes the type-I bursts, which are weak and rapid solar bursts appearing
with micro-type III bursts in the UHF frequency range. Simultaneous observations of the micro-type III/type-I bursts by these spacecraft and ground-based radio telescope, and the Hinode observation of the corresponding active region are essential to understand how continuous electron beams are generated in the active region bordering coronal holes.
Morioka et al. 2007, ApJ, 657, 567
Minoshima et al. in preparation.

 request to SOT
NFI Na I: IVDG mode, FoV: 100h x 100h, Binning: 2x2, Time resolution: 1 min, JPEG Quality: Q75, Data rate: 100 Mbits/h
SP (Fast Scan Mode) FoV 320h x 164h, Pixel size: 0.32h/pix, Binning: 2x2, Single side mode, Exposure time: 4.8 sec, JPEG Quality: Q75, Data rate: 600Mbits/map (ONE map per ONE day)

 request to XRT
FOV 512x512, 2x2 binning, Time resolution < 20sec, JPEG Q90
Al/poly (exposure time 4s) and Thin/Be (exposure time 8s) filters
Wide FOV observation (ONE image per 30 min)
FOV 1024x1024, 2x2 binning, JPEG Q90
Al/poly (short and long exposure, 256ms and 2s)

 request to EIS
Study 1: Full Scan (for steady structure, ONE scan per ONE day)
TARGET : Equatorial Coronal hole boundaries EXPOSURE TIME : 20s RASTER : Scanning SLIT : 1" STEP_SIZE : 1" FOV : 128"x256" SPECTRAL WIND.: 6 DATA COMP. : JPEG90 RASTER DURATON: 42m40s
LINES: alogT ~ 6-7,

Study 2: Fast Scan (for time evolution)
TARGET : Equatorial Coronal hole boundaries EXPOSURE TIME : 20s RASTER : Scanning SLIT : 1" STEP_SIZE : 4"
LINES: FeXII (195.12, 196.65), FeXV (284.16), FeXVI (262.98), Si VII(275.35)
Pointing: Center to boundary between the active region and coronal hole (closest to the brightest active region). Make sure to cover SOT NFI FOV.

 other participating instruments
The Iitate Planetary Radio Telescope (IPRT) of Tohoku University will be used for survey of weak solar radio phenomena such as the type-I bursts (appearing with the micro-type III bursts). This telescope makes a continuous observation of the Sun during the daytime.
Aperture area: 1000m^2
Time resolution: 10 msec
Spectral range: 100-500 MHz
Observation period: JST daytime

Observing time:
6 &#8211; 8 hours/day (23 UT &#8211; 7 UT, daytime in Japan) x 2 &#8211; 3 days
Note: These 2 - 3 days are not necessarily continuous 2 - 3 days.

(1) The observation is requested during JST daytime (23 UT &#8211; 7 UT), for co-observation with ground-based radio telescope of Japan.

(2) We can send e-mail to Hinode observers (COs) when micro-type III bursts are detected in ground-based/satellite radio observations and tell which AR may generate them.

(3) Micro-Type III associated AR may live more than one solar rotation.
If possible, please observe the same AR in the next rotation if that AR is still alive.

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