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We analyzed three noise storms recorded on 200?–?400 MHz Trieste Callisto radio spectra on 2 July 2012, 8 July 2012, and 16 July 2012 by the Fourier method. We divided intervals of the noise storms into five-minute intervals, and in these intervals we computed the mean Fourier spectra as a function of the wave numbers in the frequency and height-scale spaces. We found that these Fourier spectra, where the spectrum from the quiet-activity interval was subtracted, are power-law spectra. The mean power-law index of these spectra in the range \(\ln(k_{z}) = [1.8, 2.9]\) (where \(k_{z}\) is the wave number in the height-scale space) is \(-1.7\pm0.14\), \(-1.6\pm0.14\), and \(-1.5 \pm0.12\) for the 2 July 2012, the 8 July 2012, and the 16 July 2012 noise storms, respectively. It appears that as the number of Type-I bursts in the studied interval increases, the power-law index becomes closer to \(-5/3\); this is known as the Kolmogorov spectral index. The power-law index of the noise storms is very similar to that of the narrowband dm-spikes found in our previous studies. Furthermore, we found a break in the power spectra at \(\ln(k_{z}) \approx2.9\), and the mean power-law index values above this break are \(-2.9\pm0.46\), \(-3.1\pm0.65\), and \(-3.4\pm0.98\), respectively. 相似文献
2.
A broadband radio spectrometer has been put into operation at Bleien, Switzerland, to register the flare emission of the full
Sun. In the frequency range of operation, 0.1 to 4.0 GHz, both modes of circular polarization are recorded continuously. The
new system, Phoenix-2, has been developed from the experience with the previous Phoenix spectrometer. Improved, computer-controlled
focal hardware allows now a complete daily calibration, a more sophisticated calibration procedure, and monitoring of all
essential instrumental and environmental parameters. Calibrated data are now usually available the day after observation and
are accessible through the Internet. The scientific improvements include a larger frequency range of observation, a larger
number of completely recorded events due to full-day registration, more accurate measurements, particularly in circular polarization,
and more reliable operation. First observations are presented and quantitative results comparing the calibration with single
frequency instruments are reported.
Supplementary material to this paper is available in electronic form at http://dx.doi.org/10.1023/A:1005194314845 相似文献
3.
A new radio spectrometer, CALLISTO, is presented. It is a dual-channel frequency-agile receiver based on commercially available consumer electronics. Its major characteristic is the low price for hardware and software, and the short assembly time, both two or more orders of magnitude below existing spectrometers. The instrument is sensitive at the physical limit and extremely stable. The total bandwidth is 825 MHz, and the width of individual channel is 300 kHz. A total of 1000 measurements can be made per second. The spectrometer is well suited for solar low-frequency radio observations pertinent to space weather research. Five instruments of the type were constructed until now and put into operation at several sites, including Bleien (Zurich) and NRAO (USA). First results in the 45–870 MHz range are presented. Some of them were recorded in a preliminary setup during the time of high solar activity in October and November 2003. 相似文献
4.
Azam Zavvari Mohammad Tariqul Islam Radial Anwar Zamri Zainal Abidin Mhd Fairos Asillam Christian Monstein 《Experimental Astronomy》2016,41(1-2):185-195
The e-CALLISTO system is a worldwide network that aims to observe solar radio emission for astronomical science. CALLISTO instruments have been deployed worldwide in various locations that together can provide continuous observation of the solar radio spectrum for 24 h per day year-round. Malaysia-UKM is a strategic equatorial location and can observe the Sun 12 h per day. This paper gives an overview of the spectrum allocation for radio astronomy, which falls in the specified operating frequency band of the CALLISTO spectrometer. The radio astronomy bands are analyzed at the Malaysia-UKM station according to the International Telecommunication Union recommendations. Some observational results are also presented in this paper. 相似文献
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Using a new type of oscillation map, made from the radio spectra by the wavelet technique, we study the 18 April 2014 M7.3 flare (SOL2014-04-18T13:03:00L245C017). We find a quasi-periodic character of this flare with periods in the range 65?–?115 seconds. At the very beginning of this flare, in connection with the drifting pulsation structure (plasmoid ejection), we find that the 65?–?115 s oscillation phase slowly drifts towards lower frequencies, which indicates an upward propagating wave initiated at the start of the magnetic reconnection. Many periods (1?–?200 seconds) are found in the drifting pulsation structure, which documents multi-scale and multi-periodic processes. On this drifting structure, fiber bursts with a characteristic period of about one second are superimposed, whose frequency drift is similar to that of the drifting 65?–?115 s oscillation phase. We also checked periods found in this flare by the EUV Imaging Spectrometer (EIS)/Hinode and Interface Region Imaging Spectrograph (IRIS) observations. We recognize the type III bursts (electron beams) as proposed, but their time coincidence with the EIS and IRIS peaks is not very good. The reason probably is that the radio spectrum is a whole-disk record consisting of all bursts from any location, while the EIS and IRIS peaks are emitted only from locations of slits in the EIS and IRIS observations. 相似文献
6.
In the framework of the program for setting the Callisto spectrometer network into operation, the spectral measurements were
carried out at the sites of spectrometer locations in India and Russia in winter 2006. The results achieved at Badary, the
site where the Siberian Solar Radio Telescope (SSRT) is located, are presented. The measurements were performed using a broadband
log-periodic antenna connected to the Callisto spectrometer developed at the Institute of Astronomy (Zurich). The results
of these measurements should explain whether spectral studies at frequencies below 1 GHz can be performed using such antennas
or new antennas should be developed. The presented results are compared with the similar results obtained in Switzerland in
the frequency intervals of interest for radio astronomy. Concerning electromagnetic noise, Badary is a better site for observing
the Sun in the 50–800 MHz frequency range as compared to observatories in Switzerland. 相似文献
7.
A. O. Benz C. Monstein H. Meyer P. K. Manoharan R. Ramesh A. Altyntsev A. Lara J. Paez K.-S. Cho 《Earth, Moon, and Planets》2009,104(1-4):277-285
Radio spectrometers of the CALLISTO type to observe solar flares have been distributed to nine locations around the globe. The instruments observe automatically, their data is collected every day via internet and stored in a central data base. A public web-interface exists through which data can be browsed and retrieved. The nine instruments form a network called e-CALLISTO. It is still growing in the number of stations, as redundancy is desirable for full 24 h coverage of the solar radio emission in the meter and low decimeter band. The e-CALLISTO system has already proven to be a valuable new tool for monitoring solar activity and for space weather research. 相似文献
8.
Arnold O. Benz Christian Monstein Michael Beverland Hansueli Meyer Bruno Stuber 《Solar physics》2009,260(2):375-388
A new multichannel spectrometer, Phoenix-3, is in operation having capabilities to observe solar flare radio emissions in the 0.1?–?5 GHz range at an unprecedented spectral resolution of 61.0 kHz with high sensitivity. The present setup for routine observations allows measuring circular polarization, but requires a data compression to 4096 frequency channels in the 1?–?5 GHz range and to a temporal resolution of 200 ms. First results are presented by means of a well observed event that included narrowband spikes at 350?–?850 MHz. Spike bandwidths are found to have a power?–?law distribution, dropping off below a value of 2 MHz for full width at half maximum (FWHM). The narrowest spikes have a FWHM bandwidth less than 0.3 MHz or 0.04% of the central frequency. The smallest half-power increase occurs within 0.104 MHz at 443.5 MHz, which is close to the predicted natural width of maser emission. The spectrum of spikes is found to be asymmetric, having an enhanced low-frequency tail. The distribution of the total spike flux is approximately an exponential. 相似文献
9.
Singh Dayal Sasikumar Raja K. Subramanian Prasad Ramesh R. Monstein Christian 《Solar physics》2019,294(8):1-19
Solar Physics - In early September 2017, a series of solar flares and coronal mass ejections (CMEs) erupted from the Sun. The Cor2a coronagraph, a unit of the Sun Earth Connection Coronal and... 相似文献
10.
P. Zucca E. P. Carley J. McCauley P. T. Gallagher C. Monstein R. T. J. McAteer 《Solar physics》2012,280(2):591-602
The Rosse Solar-Terrestrial Observatory (RSTO; www.rosseobservatory.ie ) was established at Birr Castle, Co. Offaly, Ireland (53°05′38.9″, 7°55′12.7″) in 2010 to study solar radio bursts and the response of the Earth’s ionosphere and geomagnetic field. To date, three Compound Astronomical Low-cost Low-frequency Instrument for Spectroscopy in Transportable Observatory (CALLISTO) spectrometers have been installed, with the capability of observing in the frequency range of 10?–?870 MHz. The receivers are fed simultaneously by biconical and log-periodic antennas. Nominally, frequency spectra in the range of 10?–?400 MHz are obtained with four sweeps per second over 600 channels. Here, we describe the RSTO solar radio spectrometer set-up, and present dynamic spectra of samples of type II, III and IV radio bursts. In particular, we describe the fine-scale structure observed in type II bursts, including band splitting and rapidly varying herringbone features. 相似文献
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