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The dynamic spectrum, a three dimensional record of the radio intensity as a function both of time and frequency, has long been used as a probe of plasma processes in the solar corona. Beginning with the work of Wild and McCready (1950) dynamic spectroscopy has been used to distinguish between the multitude of radio wave emitting phenomena which occur in the solar corona and to infer the physical mechanisms responsible.
Stellar dynamic spectroscopy has always been a tantalizing prospect. The vast body of experience with solar dynamic spectroscopy would prove invaluable in interpreting stellar dynamic spectra. Further, the new parameter regimes presented by stellar coronas would allow further insight to be gained in the physical processes at work in stellar coronas.
Recently, Bastian and Bookbinder (1987) used the Very Large Array in spectral line mode at 1.4 GHz with a bandwidth of 50 MHz to obtain the first dynamic spectra of nearby flare stars. The spectral resolution was 3.125 MHz and the temporal resolution was 5 s. While the relative bandwidth was less than ideal (δν/ν ∼ 5%), the spectra so obtained were sufficient to show the presence of narrowband structure in a radio outburst from the well-known dMe flare star UV Ceti.
Several efforts are now underway to obtain stellar dynamic spectra, of both RS CVn binaries and dMe flare stars, with higher degrees of spectral and temporal resolution. Among these are use of a 1024 channel correlator with the 1000' telescope at Arecibo and use of the Berkeley Fast Pulsar Search Machine (Kulkarni et al. 1984) with the Green Bank 140' telescope.
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W. G. McDonald A. C. Hubbard R. G. Bookbinder K. McCamy 《Marine Geophysical Researches》1977,3(2):179-196
Ocean bottom seismographs designed to meet the requirements of both seismicity and refraction experiments have been operated extensively on twelve cruises (72 deployments). Signals from a hydrophone, and two geophones (horizontal and vertical) are direct recorded on a modified commercial tape recorder providing 10 day continuous recording at 1/40 ips and a 2–80 Hz band width. The free-fall deployment technique with timed ballast release has yielded a 93% recovery rate (96% over the most recent 24 deployments) despite frequently difficult weather and sea conditions. Emphasis on reliability and operational simplicity has produced an instrument that can be operated in arrays by a single shipboard technician.Lamont-Doherty Geological Observatory Contribution Number 2535. 相似文献
3.
Warren HP Bookbinder JA Forbes TG Golub L Hudson HS Reeves K Warshall A 《The Astrophysical journal》1999,527(2):L121-L124
The ability of the Transition Region and Coronal Explorer (TRACE) to image solar plasma over a wide range of temperatures (Te approximately 104-107 K) at high spatial resolution (0&farcs;5 pixels) makes it a unique instrument for observing solar flares. We present TRACE and Yohkoh observations of an M2.4 two-ribbon flare that began on 1999 July 25 at about 13:08 UT. We observe impulsive footpoint brightenings that are followed by the formation of high-temperature plasma (Te greater, similar10 MK) in the corona. After an interval of about 1300 s, cooler loops (Te<2 MK) form below the hot plasma. Thus, the evolution of the event supports the qualitative aspects of the standard reconnection model of solar flares. The TRACE and Yohkoh data show that the bulk of the flare emission is at or below 10 MK. The TRACE data are also consistent with the Yohkoh observations of hotter plasma (Te approximately 15-20 MK) existing at the top of the arcade. The cooling time inferred from these observations is consistent with a hybrid cooling time based on thermal conduction and radiative cooling. 相似文献
4.
Lenz Dawn D. DeLuca Edward E. Golub Leon Rosner Robert Bookbinder Jay A. Litwin Christof Reale Fabio Peres Giovanni 《Solar physics》1999,190(1-2):131-138
An initial study of long-lived loops observed with TRACE (Lenz et al., 1999) shows that they have no significant temperature stratification and that they are denser than the classic loop model
predicts. Models that agree better with the observations include a loop consisting of a bundle of filaments at different temperatures
and a loop with momentum input by MHD waves. Some implications for coronal heating models and mechanisms are discussed. 相似文献
5.
The dynamic spectrum, a three dimensional record of the radio intensity as a function both of time and frequency, has long been used as a probe of plasma processes in the solar corona. Beginning with the work of Wild and McCready (1950) dynamic spectroscopy has been used to distinguish between the multitude of radio wave emitting phenomena which occur in the solar corona and to infer the physical mechanisms responsible.Stellar dynamic spectroscopy has always been a tantalizing prospect. The vast body of experience with solar dynamic spectroscopy would prove invaluable in interpreting stellar dynamic spectra. Further, the new parameter regimes presented by stellar coronas would allow further insight to be gained in the physical processes at work in stellar coronas.Recently, Bastian and Bookbinder (1987) used the Very Large Array in spectral line mode at 1.4 GHz with a bandwidth of 50 MHz to obtain the first dynamic spectra of nearby flare stars. The spectral resolution was 3.125 MHz and the temporal resolution was 5 s. While the relative bandwidth was less than ideal (/ 5%), the spectra so obtained were sufficient to show the presence of narrowband structure in a radio outburst from the well-known dMe flare star UV Ceti.Several efforts are now underway to obtain stellar dynamic spectra, of both RS CVn binaries and dMe flare stars, with higher degrees of spectral and temporal resolution. Among these are use of a 1024 channel correlator with the 1000' telescope at Arecibo and use of the Berkeley Fast Pulsar Search Machine (Kulkarni et al. 1984) with the Green Bank 140' telescope.
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6.
R. Kano T. Sakao H. Hara S. Tsuneta K. Matsuzaki K. Kumagai M. Shimojo K. Minesugi K. Shibasaki E. E. DeLuca L. Golub J. Bookbinder D. Caldwell P. Cheimets J. Cirtain E. Dennis T. Kent M. Weber 《Solar physics》2008,249(2):263-279
The X-ray Telescope (XRT) aboard the Hinode satellite is a grazing incidence X-ray imager equipped with a 2048×2048 CCD. The XRT has 1 arcsec pixels with a wide field
of view of 34×34 arcmin. It is sensitive to plasmas with a wide temperature range from < 1 to 30 MK, allowing us to obtain
TRACE-like low-temperature images as well as Yohkoh/SXT-like high-temperature images. The spacecraft Mission Data Processor (MDP) controls the XRT through sequence tables with
versatile autonomous functions such as exposure control, region-of-interest tracking, flare detection, and flare location
identification. Data are compressed either with DPCM or JPEG, depending on the purpose. This results in higher cadence and/or
wider field of view for a given telemetry bandwidth. With a focus adjust mechanism, a higher resolution of Gaussian focus
may be available on-axis. This paper follows the first instrument paper for the XRT (Golub et al., Solar Phys.
243, 63, 2007) and discusses the design and measured performance of the X-ray CCD camera for the XRT and its control system with the MDP. 相似文献
7.
L. Golub E. DeLuca G. Austin J. Bookbinder D. Caldwell P. Cheimets J. Cirtain M. Cosmo P. Reid A. Sette M. Weber T. Sakao R. Kano K. Shibasaki H. Hara S. Tsuneta K. Kumagai T. Tamura M. Shimojo J. McCracken J. Carpenter H. Haight R. Siler E. Wright J. Tucker H. Rutledge M. Barbera G. Peres S. Varisco 《Solar physics》2007,243(1):63-86
The X-ray Telescope (XRT) of the Hinode mission provides an unprecedented combination of spatial and temporal resolution in solar coronal studies. The high sensitivity
and broad dynamic range of XRT, coupled with the spacecraft’s onboard memory capacity and the planned downlink capability
will permit a broad range of coronal studies over an extended period of time, for targets ranging from quiet Sun to X-flares.
This paper discusses in detail the design, calibration, and measured performance of the XRT instrument up to the focal plane.
The CCD camera and data handling are discussed separately in a companion paper. 相似文献
8.
Schrijver C.J. Title A.M. Berger T.E. Fletcher L. Hurlburt N.E. Nightingale R.W. Shine R.A. Tarbell T.D. Wolfson J. Golub L. Bookbinder J.A. DeLuca E.E. McMullen R.A. Warren H.P. Kankelborg C.C. Handy B.N. De Pontieu B. 《Solar physics》1999,187(2):261-302
The Transition Region and Coronal Explorer (TRACE) – described in the companion paper by Handy et al. (1999) – provides an unprecedented view of the solar outer atmosphere. In this overview, we discuss the initial impressions gained from, and interpretations of, the first million images taken with TRACE. We address, among other topics, the fine structure of the corona, the larger-scale thermal trends, the evolution of the corona over quiet and active regions, the high incidence of chromospheric material dynamically embedded in the coronal environment, the dynamics and structure of the conductively dominated transition region between chromosphere and corona, loop oscillations and flows, and sunspot coronal loops. With TRACE we observe a corona that is extremely dynamic and full of flows and wave phenomena, in which loops evolve rapidly in temperature, with associated changes in density. This dynamic nature points to a high degree of spatio-temporal variability even under conditions that traditionally have been referred to as quiescent. This variability requires that coronal heating can turn on and off on a time scale of minutes or less along field-line bundles with cross sections at or below the instrumental resolution of 700 km. Loops seen at 171 Å (～1 MK) appear to meander through the coronal volume, but it is unclear whether this is caused by the evolution of the field or by the weaving of the heating through the coronal volume, shifting around for periods of up to a few tens of minutes and lighting up subsequent field lines. We discuss evidence that the heating occurs predominantly within the first 10 to 20 Mm from the loop footpoints. This causes the inner parts of active-region coronae to have a higher average temperature than the outer domains. 相似文献
9.
The transition region and coronal explorer 总被引：5，自引：0，他引：5
Handy B.N. Acton L.W. Kankelborg C.C. Wolfson C.J. Akin D.J. Bruner M.E. Caravalho R. Catura R.C. Chevalier R. Duncan D.W. Edwards C.G. Feinstein C.N. Freeland S.L. Friedlaender F.M. Hoffmann C.H. Hurlburt N.E. Jurcevich B.K. Katz N.L. Kelly G.A. Lemen J.R. Levay M. Lindgren R.W. Mathur D.P. Meyer S.B. Morrison S.J. Morrison M.D. Nightingale R.W. Pope T.P. Rehse R.A. Schrijver C.J. Shine R.A. Shing L. Strong K.T. Tarbell T.D. Title A.M. Torgerson D.D. Golub L. Bookbinder J.A. Caldwell D. Cheimets P.N. Davis W.N. Deluca E.E. McMullen R.A. Warren H.P. Amato D. Fisher R. Maldonado H. Parkinson C. 《Solar physics》1999,187(2):229-260
The Transition Region and Coronal Explorer (TRACE) satellite, launched 2 April 1998, is a NASA Small Explorer (SMEX) that
images the solar photosphere, transition region and corona with unprecedented spatial resolution and temporal continuity.
To provide continuous coverage of solar phenomena, TRACE is located in a sun-synchronous polar orbit. The ∼700 Mbytes of data
which are collected daily are made available for unrestricted use within a few days of observation. The instrument features
a 30-cm Cassegrain telescope with a field of view of 8.5×.5 arc min and a spatial resolution of 1 arc sec (0.5 arc sec pixels).
TRACE contains multilayer optics and a lumogen-coated CCD detector to record three EUV wavelengths and several UV wavelengths.
It observes plasmas at selected temperatures from 6000 K to 10 MK with a typical temporal resolution of less than 1 min. 相似文献
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