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1.
In the years 2002 – 2005, 38 groups of the reverse drift bursts (RDBs) were observed in the 0.8 – 4.5 GHz frequency range
by the Ondřejov radiospectrograph. In 21 cases, which were observed at the times of the RHESSI observations, spatial structure,
positional changes, and spectra of X-ray sources during RDB observations are studied in detail. First, based on the frequency
drift and the spatial structure of the associated X-ray source, the events are classified as: (a) fast drifting RDBs with
a compact X-ray source, (b) fast drifting RDBs with a multiple X-ray source (FM), and slowly drifting RDBs. Then, the spectra
of X-ray sources at the times of RDBs are analyzed. It is found that most fast drifting RDBs (16 of 17 cases) are associated
with the spectra having a distinct power-law (non-thermal) component. In contrast, the X-ray spectra associated with the slowly drifting RDBs are predominantly purely
thermal (in three out of four cases; in the 26 July 2004, case the X-ray spectrum is thermal and high temperature, with non-thermal
component). Two special cases of RDBs observed during the 28 October 2003, and 23 July 2004, flares are added for comparison.
The most frequent events are those with fast drifting RDBs, a compact short-lasting X-ray sources, and a power-law X-ray spectrum.
The individual reverse drift bursts (∼1 s duration) do not show a clear temporal association with individual peaks of hard
X-ray bursts. During slowly drifting RDBs the shape of the associated X-ray source changed or expanded. Among them the most
interesting one was observed in 26 July 2004, when the very slowly drifting RDBs (+40 MHz s−1) were associated with an X-ray loop-like source continuously elongating in the southwest direction. In the most cases the
model of RDBs with electron beams is compatible with the observations, but in flares on 26 July 2004, and 28 October 2003,
the RDBs are probably generated by some other type of an agent; we propose here a thermal conduction front. 相似文献
2.
Through the data around 3 GHz from the Radio Spectrometer in Huairou, Beijing, zebra-pattern structures from the 21 April
2002 event have been studied. Zebra stripes consist of periodically pulsating superfine structures in this event. An analysis
of temporal profiles of intensities at multiple frequency channels shows that the Gaussian temporal profiles of pulse groups
on zebra stripes are caused by drifting zebra stripes with Gaussian spectral profiles. The observed quasiperiodic pulsations
with about 30 ms period have a peculiar feature of oscillation near a steady state, probably resulting from relaxation oscillations,
which modulate the electron cyclotron maser emission that forms the zebra stripes during the process of wave – particle interactions.
All the main properties of the zebra stripes with pulsating superfine structures indicate that the double plasma resonance
model might be the most suitable one, with the relaxation oscillations, to form the superfine structures. The model of LaBelle
et al. (Astrophys. J.
593, 1195, 2003) could not account for the observed properties of zebra-pattern structures in this event nor for most zebra-pattern structures
occupying a wide frequency range, mainly because the allowable frequency range of the zebra-pattern structures in their model
is too narrow to reproduce the observed zebras. 相似文献
3.
Y. Suematsu S. Tsuneta K. Ichimoto T. Shimizu M. Otsubo Y. Katsukawa M. Nakagiri M. Noguchi T. Tamura Y. Kato H. Hara M. Kubo I. Mikami H. Saito T. Matsushita N. Kawaguchi T. Nakaoji K. Nagae S. Shimada N. Takeyama T. Yamamuro 《Solar physics》2008,249(2):197-220
The Solar Optical Telescope (SOT) aboard the Solar-B satellite (Hinode) is designed to perform high-precision photometric and polarimetric observations of the Sun in visible light spectra (388 – 668 nm)
with a spatial resolution of 0.2 – 0.3 arcsec. The SOT consists of two optically separable components: the Optical Telescope
Assembly (OTA), consisting of a 50-cm aperture Gregorian with a collimating lens unit and an active tip-tilt mirror, and an
accompanying Focal Plane Package (FPP), housing two filtergraphs and a spectro-polarimeter. The optomechanical and optothermal
performance of the OTA is crucial to attain unprecedented high-quality solar observations. We describe in detail the instrument
design and expected stable diffraction-limited on-orbit performance of the OTA, the largest state-of-the-art solar telescope
yet flown in space. 相似文献
4.
We analyze the high-frequency drift radio structures observed by the spectrometer at Purple Mountain Observatory (PMO) over
the frequency range of 4.5 – 7.5 GHz during the 18 March 2003 solar flare. The drifting structures take place before the soft
X-ray maximum, almost at the maximum of hard X-ray flux at 25 – 50 keV. For the first time, the positive drift in this kind
of radio structures is detected in such a high frequency range. Their global drifting rate is roughly estimated as 3.6 GHz s−1. They appear in four groups, lasting in total for less than 6 s, and have a broad bandwidth of more than 2 GHz but a smaller
ratio of the bandwidth of the drifting structures to mean frequency than that of the lower frequency range. The lifetime of
each individual burst in this event can be derived by using the high temporal resolution of the spectrometer at PMO and has
an average value of 36.3 ms. Since the negative drifting structures observed in the 0.6 – 4.5 GHz frequency range were interpreted
to be a radio signature of a plasmoid ejected upward (moving out of the Sun), the present observation may imply that it is
possible for a plasmoid to move downward during a solar flare. However, for a confirmation of this suggestion direct radio
imaging observation would be needed. 相似文献
5.
Ulysses was launched in October 1990, and its Solar X-ray/Cosmic Gamma-Ray Burst Experiment (GRB) has provided more than 13 years
of uninterrupted observations of solar X-ray flare activity. Due to the large variation of the relative solar latitude and
longitude of the spacecraft orbit with respect to the Earth, the perspective of the GRB instrument often differed significantly
from that of X-ray instruments on Earth-orbiting satellites. During extended periods the GRB experiment made direct observations
of flares on the hidden face of the Sun, providing a unique record of events not visible to other instruments. The small detector
area of GRB and its optimization for very high counting rates minimized the effects of pulse pile-up. We interpret the spectra,
time histories, and occurrence distribution patterns of GRB data in terms of “thermal feed-through”, the confusion of thermal
soft X-rays and non-thermal hard X-rays. This effect is a systematic problem for scintillation-counter spectrometers observing
the solar hard X-ray spectrum. This paper provides a definitive catalog of the Ulysses X-ray flare observations and discusses various features of this unique database. For the equivalent GOES range X2 – X25,
we find a power-law fit for the (differential) occurrence frequency at >25 keV with slope −1.61±0.04, with no evidence for
a downturn at the highest event magnitudes (for the relatively small sample of such events available in this study). If the
nine most intense events are excluded because of concerns about the effects of pulse pile-up, the slope steepens to −1.75±0.08. 相似文献
6.
As part of a program to estimate the solar spectrum back to the early twentieth century, we have generated fits to UV spectral
irradiance measurements from 1 – 410 nm. The longer wavelength spectra (150 – 410 nm) were fit as a function of two solar
activity proxies, the Mg ii core-to-wing ratio, or Mg ii index, and the total Ca ii K disk activity derived from ground based observations. Irradiance spectra at shorter wavelengths (1 – 150 nm) where used
to generate fits to the Mg ii core-to-wing ratio alone. Two sets of spectra were used in these fitting procedures. The fits at longer wavelengths (150
to 410 nm) were derived from the high-resolution spectra taken by the Solar Ultraviolet Spectral Irradiance Monitor (SUSIM)
on the Upper Atmospheric Research Satellite (UARS). Spectra measured by the Solar EUV Experiment (SEE) instrument on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite were used for the fits at wavelengths from 1 to 150 nm. To generate fits between solar irradiance and solar
proxies, this study uses the above irradiance data, the NOAA composite Mg ii index, and daily Ca ii K disk activity determined from images measured by Big Bear Solar Observatory (BBSO). In addition to the fitting coefficients
between irradiance and solar proxies, other results from this study include an estimated relationship between the fraction
of the disk with enhanced Ca ii K activity and the Mg ii index, an upper bound of the average solar UV spectral irradiance during periods where the solar disk contains only regions
of the quiet Sun, as was believed to be present during the Maunder Minimum, as well as results indicating that slightly more
than 60% of the total solar irradiance (TSI) variability occurs between 150 and 400 nm. 相似文献
7.
G. Trottet J.-P. Raulin G. Giménez de Castro T. Lüthi A. Caspi C. H. Mandrini M. L. Luoni P. Kaufmann 《Solar physics》2011,273(2):339-361
Solar flares observed in the 200 – 400 GHz radio domain may exhibit a slowly varying and time-extended component which follows
a short (few minutes) impulsive phase and can last for a few tens of minutes to more than one hour. The few examples discussed
in the literature indicate that such long-lasting submillimeter emission is most likely thermal bremsstrahlung. We present
a detailed analysis of the time-extended phase of the 27 October 2003 (M6.7) flare, combining 1 – 345 GHz total-flux radio
measurements with X-ray, EUV, and Hα observations. We find that the time-extended radio emission is, as expected, radiated
by thermal bremsstrahlung. Up to 230 GHz, it is entirely produced in the corona by hot and cool materials at 7 – 16 MK and
1 – 3 MK, respectively. At 345 GHz, there is an additional contribution from chromospheric material at a few 104 K. These results, which may also apply to other millimeter–submillimeter radio events, are not consistent with the expectations
from standard semiempirical models of the chromosphere and transition region during flares, which predict observable radio
emission from the chromosphere at all frequencies where the corona is transparent. 相似文献
8.
Marta M. Cassiano Pierre Kaufmann Rogério Marcon Amauri S. Kudaka Adolfo Marun Rodolfo Godoy Pablo Pereyra Arline M. Melo Hugo Levato 《Solar physics》2010,264(1):71-79
Solar observations in the mid-infrared 8 – 14 μm band continuum were carried out with cadence of 5 frames per second, in December 2007.
Rapid small heated sources, with a typical duration of the order of seconds, were found on the bright plage-like areas around
sunspots, in association with relatively weak GOES soft X-ray bursts. This work presents the analysis of fast mid-infrared
flashes detected during a GOES B2.0-class event on 10 December 2007, beginning at about 10:40 UT. Rapid brightness temperature
enhancements of 0.5 to 2.0 K were detected at the Earth by a microbolometer array, using a telescope with 10.5 cm diameter
aperture producing a diffraction-limited photometric beam of 25 arc sec. The minimum detectable temperature change was of
0.1 K. The corresponding fluxes are 30 – 130 solar flux units. At the solar surface the estimated rapid brightenings represented
a temperature enhancement of 50 – 150 K. 相似文献
9.
Rajmal Jain Arun Kumar Awasthi Arvind Singh Rajpurohit Markus J. Aschwanden 《Solar physics》2011,270(1):137-149
We report solar flare plasma to be multi-thermal in nature based on the theoretical model and study of the energy-dependent
timing of thermal emission in ten M-class flares. We employ high-resolution X-ray spectra observed by the Si detector of the
“Solar X-ray Spectrometer” (SOXS). The SOXS onboard the Indian GSAT-2 spacecraft was launched by the GSLV-D2 rocket on 8 May
2003. Firstly we model the spectral evolution of the X-ray line and continuum emission flux F(ε) from the flare by integrating a series of isothermal plasma flux. We find that the multi-temperature integrated flux F(ε) is a power-law function of ε with a spectral index (γ)≈−4.65. Next, based on spectral-temporal evolution of the flares we find that the emission in the energy range E=4 – 15 keV is dominated by temperatures of T=12 – 50 MK, while the multi-thermal power-law DEM index (δ) varies in the range of −4.4 and −5.7. The temporal evolution of the X-ray flux F(ε,t) assuming a multi-temperature plasma governed by thermal conduction cooling reveals that the temperature-dependent cooling
time varies between 296 and 4640 s and the electron density (n
e) varies in the range of n
e=(1.77 – 29.3)×1010 cm−3. Employing temporal evolution technique in the current study as an alternative method for separating thermal from nonthermal
components in the energy spectra, we measure the break-energy point, ranging between 14 and 21±1.0 keV. 相似文献
10.
We explore the hard X-ray source distributions of an C1.1 flare occurred on 14 December 2007. Both Hinode/EIS and RHESSI observations are used. One of EIS rasters perfectly covers the double hard X-ray footpoints, where the EUV
emission appears strong from the cool line of He ii (log T=4.7) to the hot line of Fe xvi (log T=6.4). We analyze RHESSI X-ray images at different energies and different times before the hard X-ray maximum. The results
show a similar topology for the time-dependent source distribution (i.e. at 14:14:35 UT) as that for energy-dependent source distribution (i.e. at a given energy band of 6 – 9 keV) overlapped on EUV bright kernels, which seems to be consistent with the evaporation
model. 相似文献
11.
We report very high temporal and spectral resolution interferometric observations of some unusual solar radio bursts near
1420 MHz. These bursts were observed on 13 September 2005, 22 minutes after the peak of a GOES class X flare from the NOAA
region 10808. Our observations show 11 episodes of narrow-band intermittent emission within a span of ≈ 8 s. Each episode
shows a heavily frequency-modulated band of emission with a spectral slope of about −245.5 MHz s−1, comprising up to 8 individual blobs of emission and lasts for 10 – 15 ms. The blobs themselves have a spectral slope of
≈ 0 MHz s−1, are ≈ 200 – 250 kHz wide, appear every ≈ 400 kHz and last for ≈ 4 – 5 ms. These bursts show brightness temperatures in the
range 1012 K, which suggests a coherent emission mechanism. We believe these are the first high temporal and spectral resolution interferometric
observations of such rapid and narrow-bandwidth solar bursts close to 1420 MHz and present an analysis of their temporal and
spectral characteristics. 相似文献
12.
Zongjun Ning 《Solar physics》2011,273(1):81-92
We explore the speed distributions of X-ray source motions after the start of chromospheric evaporation in two Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) flares. First, we make CLEAN images at 15 energy bands with a 12 second integration window; then, we outline a flaring
loop geometry to cover the looptop and footpoint sources as much as possible. Consistent with the previous steps, we find
converging motion of the double footpoint sources along the flaring loop in these two events. This motion is dependent on
the energy band and time and is typically seen at 3 – 25 keV, indicating a chromospheric evaporation origin. The speed distributions
at various energy bands are measured for the 10 September 2002 flare, which exhibits a separation-to-mergence motion pattern
well correlated with the rising-to-decay phases at 50 – 100 keV. 相似文献
13.
Werner M. Neupert 《Solar physics》2011,272(2):319-335
The two-band soft X-ray observations of solar flares made by the Naval Research Laboratory’s (NRL) SOLar RADiation (SOLRAD)
satellites and by the Geostationary Orbiting Environmental Satellites (GOES) operated by the National Oceanic and Atmospheric Administration’s (NOAA) Space Weather Prediction Center have produced
a nearly continuous record of solar flare observations over a period of more than forty years (1969 – 2011). However, early
GOES observations (i.e., GOES-2) and later (GOES-8 and subsequent missions) are not directly comparable due to changes in the conversion of measured
currents to integrated fluxes in the two spectral bands that were adopted: 0.05 – 0.3 (or 0.4) nm, which we refer to as XS
and 0.1 – 0.8 nm (XL). Furthermore, additional flux adjustments, using overlapping data sets, were imposed to provide consistency
of flare-flux levels from mission to mission. This article evaluates the results of these changes and compares experimental
GOES-8/GOES-2 results with changes predicted from modeled flare spectra. The factors by which recent GOES observations can
be matched to GOES-2 are then optimized by adapting a technique first used to extrapolate GOES X-ray fluxes above saturation
using ionospheric VLF radio phase enhancements. A nearly 20% increase in published GOES-8 XL data would be required to match
to GOES-2 XL fluxes, which were based on observed flare spectra. On the other hand, a factor of 1.07 would match GOES-8 and
later flat-spectrum 0.1 – 0.8 nm fluxes to GOES-2 XL if the latter data were converted to a flat-spectrum basis. Finally,
GOES-8 observations are compared to solar soft X-ray estimates made concurrently with other techniques. Published GOES-8 0.1 – 0.8 nm
fluxes are found to be 0.59 of the mean of these other determinations. Rescaling GOES to a realistic flare spectrum and removing
a 30% downward adjustment applied to the GOES-8 measurements during initial data processing would place GOES-8 and later GOES
XL fluxes at 0.94 of this XL mean. GOES-2 on the same scale would lie at about 0.70 of this mean. Significant uncertainties
in the absolute levels of broad band soft X-ray fluxes still remain, however. 相似文献
14.
P. Rudawy K. J. H. Phillips A. Buczylko D. R. Williams F. P. Keenan 《Solar physics》2010,267(2):305-327
Some 8000 images obtained with the Solar Eclipse Coronal Imaging System (SECIS) fast-frame CCD camera instrument located at Lusaka, Zambia, during the total eclipse of 21 June 2001 have been analysed
to search for short-period oscillations in intensity that could be a signature of solar coronal heating mechanisms by MHD
wave dissipation. Images were taken in white-light and Fe xiv green-line (5303 ?) channels over 205 seconds (frame rate 39 s−1), approximately the length of eclipse totality at this location, with a pixel size of four arcseconds square. The data are
of considerably better quality than those that we obtained during the 11 August 1999 total eclipse (Rudawy et al.: Astron. Astrophys. 416, 1179, 2004), in that the images are much better exposed and enhancements in the drive system of the heliostat used gave a much improved
image stability. Classical Fourier and wavelet techniques have been used to analyse the emission at 29 518 locations, of which
10 714 had emission at reasonably high levels, searching for periodic fluctuations with periods in the range 0.1 – 17 seconds
(frequencies 0.06 – 10 Hz). While a number of possible periodicities were apparent in the wavelet analysis, none of the spatially
and time-limited periodicities in the local brightness curves was found to be physically important. This implies that the
pervasive Alfvén wave-like phenomena (Tomczyk et al.: Science
317, 1192, 2007) using polarimetric observations with the Coronal Multi-Channel Polarimeter (CoMP) instrument do not give rise to significant oscillatory intensity fluctuations. 相似文献
15.
We investigate the properties of acoustic events (AEs), defined as spatially concentrated and short duration energy flux,
in the quiet Sun, using observations of a 2D field of view (FOV) with high spatial and temporal resolution provided by the
Solar Optical Telescope (SOT) onboard Hinode. Line profiles of Fe i 557.6 nm were recorded by the Narrow-band Filter Imager (NFI) on a 82″×82″ FOV during 75 min with a time step of 28.75 s
and 0.08″ pixel size. Vertical velocities were computed at three atmospheric levels (80, 130, and 180 km) using the bisector
technique, allowing the determination of energy flux to be made in the range 3 – 10 mHz using two complementary methods (Hilbert
transform and Fourier power spectrum). Horizontal velocities were computed using local correlation tracking (LCT) of continuum
intensities providing divergences. We found that the net energy flux is upward. In the range 3 – 10 mHz, a full FOV space
and time averaged flux of 2700 W m−2 (lower layer 80 – 130 km) and 2000 W m−2 (upper layer 130 – 180 km) is concentrated in less than 1 % of the solar surface in the form of narrow (0.3″) AE. Their total
duration (including rise and decay) is of the order of 103 s. Inside each AE, the mean flux is 1.6×105 W m−2 (lower layer) and 1.2×105 W m−2 (upper). Each event carries an average energy (flux integrated over space and time) of 2.5×1019 J (lower layer) to 1.9×1019 J (upper). More than 106 events could exist permanently on the Sun, with a birth and decay rate of 3500 s−1. Most events occur in intergranular lanes, downward velocity regions, and areas of converging motions. 相似文献
16.
We revisit the flare that occurred on 13 January 1992, which is now universally termed the “Masuda flare”. The new analysis
is motivated not just by its uniqueness despite the increasing number of coronal observations in hard X-rays, but also by
the improvement of Yohkoh hard X-ray image processing, which was achieved after the intensive investigations on this celebrated event. Using an uncertainty
analysis, we show that the hard X-ray coronal source is located closer to the soft X-ray loop by about 5000 km (or 7 arcsec)
in the re-calibrated Hard X-ray Telescope (HXT) images than in the original ones. Specifically, the centroid of the M1-band
(23 – 33 keV) coronal source is above the maximum brightness of the Soft X-ray Telescope (SXT) loop by 5000±1000 km (9600
km in the original data) and above the apex of the SXT loop represented by the 30% brightness contour by 2000±1000 km (∼ 7000 km
in the original data). The change is obviously significant, because most coronal sources are above the thermal loop by less
than 6 arcsec. We suggest that this change may account for the discrepancy in the literature, i.e., the spectrum of the coronal emission was reported to be extremely hard below ∼ 20 keV in the pre-calibration investigations,
whereas it was reported to be considerably softer in the literature after the re-calibration done by Sato, Kosugi, and Makishima
(Pub. Astron. Soc. Japan
51, 127, 1999). Still, the coronal spectrum is flatter at lower energies than at higher energies, due to the lack of a similar, co-spatial
source in the L-band (14 – 23 keV), for which a convincing explanation is absent. 相似文献
17.
We study the relationship between the brightness (I) and magnetic field (B) distributions of sunspots using 272 samples observed at the San Fernando Observatory and the National Solar Observatory,
Kitt Peak, whose characteristics varied widely. We find that the I – B relationship has a quadratic form for the spots with magnetic field less than about 2000 G. The slope of the linear part
of the I – B curve varies by about a factor of three for different types of spots. In general the slope increases as the spot approaches
disk center. The I – B slope does not have a clear dependency on the spot size but the lower limit appears to increase as a function of the ratio
of umbra and penumbra area. The I – B slope changes as a function of age of the sunspots. We discuss various sunspot models using these results. 相似文献
18.
Hiroko Watanabe Alexandra Tritschler Reizaburo Kitai Kiyoshi Ichimoto 《Solar physics》2010,266(1):5-16
We performed two-dimensional spectroscopic observations of the preceding sunspot of NOAA 10905 located off disk center (S8
E36, μ≈0.81) by using the Interferometric BI-dimensional Spectrometer (IBIS) operated at the Dunn Solar Telescope (DST) of the National
Solar Observatory, New Mexico. The magnetically insensitive Fe I line at 709.04 nm was scanned in wavelength repetitively
at an interval of 37 s to calculate sequences of maps of the line-wing and line-core intensity, and the line-of-sight Doppler
velocity at different line depths (3% to 80%). Visual inspection of movies based on speckle reconstructions computed from
simultaneous broadband data and the local continuum intensity at 709.04 nm revealed an umbral dot (UD) intruding rapidly from
the umbral boundary to the center of the umbra. The apparent motion of this object was particularly fast (1.3 km s−1) when compared to typical UDs. The lifetime and size of the UD was 8.7 min and 240 km, respectively. The rapid UD was visible
even in the line-core intensity map of Fe I 709.04 nm and was accompanied by a persistent blueshift of about 0.06 km s−1. 相似文献
19.
We studied the kinematic evolution of the 8 October 2007 CME in the corona based on observations from Sun – Earth Connection Coronal and Heliospheric Investigation (SECCHI) onboard satellite B of Solar TErrestrial RElations Observatory (STEREO). The observational results show that this CME obviously deflected to a lower latitude region of about 30° at the
beginning. After this, the CME propagated radially. We also analyze the influence of the background magnetic field on the
deflection of this CME. We find that the deflection of this CME at an early stage may be caused by a nonuniform distribution
of the background magnetic-field energy density and that the CME tended to propagate to the region with lower magnetic-energy
density. In addition, we found that the velocity profile of this gradual CME shows multiphased evolution during its propagation
in the COR1-B FOV. The CME velocity first remained constant: 23.1 km s−1. Then it accelerated continuously with a positive acceleration of ≈7.6 m s−2. 相似文献
20.
T. Shimizu S. Nagata S. Tsuneta T. Tarbell C. Edwards R. Shine C. Hoffmann E. Thomas S. Sour R. Rehse O. Ito Y. Kashiwagi M. Tabata K. Kodeki M. Nagase K. Matsuzaki K. Kobayashi K. Ichimoto Y. Suematsu 《Solar physics》2008,249(2):221-232
The Hinode Solar Optical Telescope (SOT) is the first space-borne visible-light telescope that enables us to observe magnetic-field
dynamics in the solar lower atmosphere with 0.2 – 0.3 arcsec spatial resolution under extremely stable (seeing-free) conditions.
To achieve precise measurements of the polarization with diffraction-limited images, stable pointing of the telescope (<0.09 arcsec,
3σ) is required for solar images exposed on the focal plane CCD detectors. SOT has an image stabilization system that uses image
displacements calculated from correlation tracking of solar granules to control a piezo-driven tip-tilt mirror. The system
minimizes the motions of images for frequencies lower than 14 Hz while the satellite and telescope structural design damps
microvibration in higher frequency ranges. It has been confirmed from the data taken on orbit that the remaining jitter is
less than 0.03 arcsec (3σ) on the Sun. This excellent performance makes a major contribution to successful precise polarimetric measurements with 0.2 – 0.3 arcsec
resolution.
K. Kobayashi now at NASA/Marshall Space Flight Center, Huntsville, AL 35812, USA. 相似文献