共查询到20条相似文献，搜索用时 437 毫秒
1.
J.J. Riihimaa T.D. Carr R.S. Flagg W.B. Greenman P.P. Gombola G.R. Lebo J.A. Levy 《Icarus》1981,48(2):298-307
High-resolution dynamic spectra of Jovian S-bursts frequently reveal sloping gaps crossing bands of L-burst emission with drift rates comparable to those of S-bursts. These “fast-drift shadow” (FDS) events are often sharply bounded on one edge by an S-burst, and sometimes on both edges by a pair of S-bursts emanating from a common vertex. It is suggested that the investigation of such S- and L-burst interactions may provide new insights of considerable importance in the search for the Jovian decametric emission mechanism. 相似文献
2.
Dynamic spectra of Jupiter's decametric emission are observed with a high-resolution radio spectrograph. Certain events observed in region Io-B display interaction effects between the S- and L-emissions. The effect appears as a gap in the L-emission after a passage of an S-burst. In a typical case the L-emission has a relatively narrow bandwidth, the S-burst appears as a sloping line crossing it, and the duration of the emission gap is a substantial fraction of a second. The gap has sharp, sloped edges; its leading edge has anf-t slope which is the same as that of the S-burst while the slope of the trailing edge is lower. A kind of tilted V-pattern is thus formed. It is suggested that some more complicated spectral patterns may also be produced this way. It seems that an emission model consisting of S-bursts from bunches of gyrofrequency-emitting electrons ascending a flux tube and interacting with L-emitting bunches of electrons having more stationary guiding centers is inadequate to explain the complex S-L interactions.Contribution of No. 36 of the Department of Astronomy, University of Florida, U.S.A. 相似文献
3.
The Io flux tube (IFT), along which Io interacts with the Jovian magnetosphere, is the place of plasma acceleration processes resulting in auroral like emissions, in UV, IR and Radio emissions in the decameter range. At Earth, the study of the acceleration processes is mainly made by in situ measurements. Acceleration processes at Jupiter were first deduced from the observation of a particular kind of decameter radio emissions from the IFT: the short (S-)bursts. These radio bursts present a negative drift in the time-frequency domain, which is related to the motion of the energetic electrons which produce them. The measure of their drift thus permits the kinetic energy of the electrons to be obtained, as well as its variations along the IFT which have been interpreted as electric potential jumps. Using an enhanced S-burst detection and drift measurement method, more than 1 h of quasi-continuous decametric emissions recorded at the Kharkov UTR-2 radiotelescope have been analyzed. We observe the evolution of the electron kinetic energy with the longitude of Io with a resolution of , and detect the presence of acceleration structures with characteristics being consistent with electric potential jumps of few hundred volts, and moving along the IFT in the upward direction (toward Io) at the local sound velocity. 相似文献
4.
We present the results of a study of the relationship of a complex meter-decameter wavelength radio burst observed with the Clark Lake E-W and N-S interferometers, with a hard X-ray burst observed with the X-ray spectrometer aboard ISEE-3. The radio burst consisted of several type III's, reverse drift type III's, a U burst, and type II and type IV bursts. The X-ray emission was also complex. The radio as well as hard X-ray emissions were observed before the flash phase of the flare; they were not always associated and we conjecture that this may constitute evidence for acceleration of electrons high in the corona. On the other hand, all components of the reverse drift burst were associated with hard X-ray subpeaks, indicating multiple injection of electron beams along field lines with different density gradients. While the type II burst appeared to be related to the hard X-ray burst, a detailed correspondence between individual features of the radio and hard X-ray burst emissions could not be found. The type IV burst started after all hard X-ray emissions ceased. Its source appeared to be a magnetic arch, presumably containing energetic electrons responsible for the gyrosynchrotron radiation of type IV.Presently at INPE/CRAAM, São Paulo, Brazil. 相似文献
5.
Wang Shujuan Yan Yihua Zhao Ruizhen Fu Qijun Tan Chengming Xu Long Wang Shijin Lin Huaan 《Solar physics》2001,204(1-2):153-164
25 MHz–7.6 GHz global and detailed (fine structure – FS) radio spectra are presented, which were observed in the NOAA 9077
active region for the Bastille Day (14 July 2000) flare at 10:10–11:00 UT. Besides broadband radio bursts, high-resolution
dynamic spectra reveal metric type II burst, decimetric type IV burst and various decimetric and microwave FSs, such as type III
bursts, type U bursts, reverse-slope (RS)-drifting burst, fiber bursts, patch and drifting pulsation structure (DPS). The
peak-flux-density spectrum of the radio bursts over the range 1.0–7.6 GHz globally appears as a U-shaped signature. Analyzing
the features of backbone and herringbones of the type II burst, the speeds of shock and relevant energetic electron beams
were estimated to be 1100 km s−1 and 58 500 km s−1, respectively. Also the time sequence of the radio emission is analyzed by comparing with the hard X-rays (HXRs) and the
soft X-rays (SXRs) in this flare. After the maxima of the X-rays, the radio emission in the range 1.0–7.6 GHz reached maxima
first at the higher frequency, then drifted to the lower frequency. This comparison suggested that the flare included three
successive processes: firstly the X-rays rose and reached maxima at 10:10–10:23 UT, accompanied by fine structures only in
the range 2.6–7.6 GHz; secondly the microwave radio emission reached maxima accompanied by many fine structures over the range
1.0–7.6 GHz at 10:23–10:34 UT; then a decimetric type IV burst and its associated FSs (fibers) in the range 1.0–2.0 GHz appeared
after 10:40 UT. 相似文献
6.
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
7.
Ya. G. Tsybko 《Solar physics》1984,92(1-2):299-315
Type-IIIb, IIId, and III solar decametric radio bursts, being distinguished by the typical negative drift rate of their dynamic spectra, are compared. Observational data were obtained with a UTR-2 antenna during the period 1973–1982. During the analysis of the bursts of all these spectral varieties, the frequency drift time (drift delay) was measured in the ranges 25 to 12.5 MHz, 25 to 20 MHz, and 12.5 to 10 MHz. Durations of type-III bursts were determined at the harmonically-related frequencies of 25 and 12.5 MHz; radio source locations were also used.It is shown that these decametric bursts are distinctly divided into two groups: (1)type-IIIb chains of simple stria bursts and also normal type-III storm bursts observed at central regions constitute a group of events with a fast drifting spectrum; (2) type-III bursts from type-IIIb-III pairs and the limb variant of normal III bursts, as well as peculiar type-IIId chains of diffuse striae and related chains with an echo component, constitute a second group of events with comparatively slow drift rates.The first group of the phenomena is associated with the fundamental F frequency and the second one, with the harmonic H of the coronal plasma frequency. The results of the present investigation agree well with earlier conclusions on the harmonic origin of decametric chains and type-III bursts. Measurements of drift delays in narrow frequency ranges, an octave apart, as well as type-III burst durations at harmonically-related frequencies confirm the existence of both F and H components in the solar radiation. The essential result of 10 years of decametric observations is that the frequency drift rates and durations are rather stable parameters for the various type-III bursts and stria-burst chains. The stability characterizes some unspecified conditions of burst generation in the middle corona. 相似文献
8.
We investigate the relative timing between hard X-ray (HXR) peaks and structures in metric and decimetric radio emissions
of solar flares using data from the RHESSI and Phoenix-2 instruments. The radio events under consideration are predominantly
classified as type III bursts, decimetric pulsations and patches. The RHESSI data are demodulated using special techniques
appropriate for a Phoenix-2 temporal resolution of 0.1 s. The absolute timing accuracy of the two instruments is found to
be about 170 ms, and much better on the average. It is found that type III radio groups often coincide with enhanced HXR emission,
but only a relatively small fraction (∼20%) of the groups show close correlation on time scales < 1 s. If structures correlate,
the HXRs precede the type III emissions in a majority of cases, and by 0.69 ± 0.19 s on the average. Reversed drift type III
bursts are also delayed, but high-frequency and harmonic emission is retarded less. The decimetric pulsations and patches
(DCIM) have a larger scatter of delays, but do not have a statistically significant sign or an average different from zero.
The time delay does not show a center-to-limb variation excluding simple propagation effects. The delay by scattering near
the source region is suggested to be the most efficient process on the average for delaying type III radio emission. 相似文献
9.
We report here the observation of a rare solar radio event at hectometric wavelengths that was characterized by essentially
100% circularly polarized radiation and that was observed continuously for about six days, from May 17 to 23, 2002. This was
the first time that a solar source with significantly polarized radiation was detected by the WAVES experiment on the
Wind spacecraft. From May 19 to 22, the intense polarized radio emissions were characterized by quasi-periodic intensity variations
with periods from one to two hours and with superposed drifting, narrowband, fine structures. The bandwidth of this radiation
extended from about 400 kHz to 7 MHz, and the peak frequency of the frequency spectrum slowly decreased from 2 MHz to about
0.8 MHz over the course of four days. The radio source, at each frequency, was observed to slowly drift from east to west
about the Sun, as viewed from the Earth and was estimated to lie between 26 and 82R⊙ (R⊙ = 696 000 km). We speculate that this unusual event may represent an interplanetary manifestation of a moving type IV burst
and discuss possible radio emission mechanisms. The ISEE-3 spacecraft may possibly have detected a similar event some 26 years
ago. 相似文献
10.
Huang Guang-Li Qin Zhi-Hai Yan Guo Fu Qi-Jun Liu Yu-Ying 《Astrophysics and Space Science》1998,259(3):317-326
A typical event of solar microwave type III burst with both positive and negative frequency drifts was observed by the 1–2
GHz spectrograph at Beijing Observatory on January 5, 1994. The separatrix frequency (1.3 GHz) may correspond to an acceleration
region. The energy of the electron beam responsible for the burst is calculated from the drift rate and the height of the
source above the photosphere. Moreover, if the solar microwave type III burst is explained by the beam-plasma instability
as suggested by Huang (1998), the energy density as well as the particle density of the electron beam may be estimated from
the burst flux, the growth rates and the modularity (Huang et al., 1996). So that, a very good power- law distribution is
simulated for the energetic spectrum of the electron beam in this event with a spectrum index 4.5. The electron beam may be
accelerated by an electric field with a length of 107 m and a strength of <10-4 V m- 1. These results are necessary for understanding the acceleration process in solar flares.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
11.
A. Böhme F. Fürstenberg J. Hildebrandt O. Saal A. Krüger P. Hoyng G. A. Stevens 《Solar physics》1977,53(1):139-155
A two-component (core-halo) emission model has been applied reconciling hard and soft X-ray burst emissions with the microwave burst radiation. The core region is represented by a nonthermal energy distribution (Maxwellian+power law tail) and assumed to be surrounded by a thermal halo. Parameters characterizing the energy distribution and emission measures have been derived numerically from soft and hard X-ray measurements. Using an artificial magnetic field model the microwave flux spectrum has been calculated on the basis of gyro-synchrotron emission and absorption by solving the equation of radiation transfer along the ray trajectories. Open parameters were used to adapt the spectrum to the radio measurements.Thus probable informations about the most appropriate magnetic field parameters as well as about the time- and frequency- dependent source diameters (yielding growth velocities of the core region during the impulsive phase) are deduced for the burst of 1972 May 18 as an example. A fit of the observed spectrum at the burst maximum is consistent with a magnetic field of 150O G at the core centre decreasing up to about 40 G at the top of the halo at a height of 50 000 km above the centre, a core density of 1010 cm–3 decreasing to 109 cm–3 at the outer halo boundary, and a core diameter of 15 000 km (]20).Due to the simple geometry and emission process adopted,- the model refers primarily to special impulsive bursts. For the representation of broad band microwave bursts, e.g. type IV , events, a more complex source geometry and/or other variants of the emission mechanism must be invoked. 相似文献
12.
The Source Regions of Impulsive Solar Electron Events 总被引：1，自引：0，他引：1
Benz Arnold O. Lin Robert P. Sheiner Olga A. Krucker Säm Fainberg Joe 《Solar physics》2001,203(1):131-144
Low-energy (2–19 keV) impulsive electron events observed in interplanetary space have been traced back to the Sun, using their interplanetary type III radiation and metric/decimetric radio-spectrograms. For the first time we are able to study the highest frequencies and thus the radio signatures closest to the source region. All the selected impulsive solar electron events have been found to be associated with an interplanetary type III burst. This allows to time the particle events at the 2 MHz plasma level and identify the associated coronal radio emissions. Except for 5 out of 27 cases, the electron events were found to be associated with a coronal type III burst in the metric wavelength range. The start frequency yields a lower limit to the density in the acceleration region. We also search for narrow-band spikes at the start of the type III bursts. In about half of the observed cases we find metric spikes or enhancements of type I bursts associated with the start of the electron event. If interpreted as the plasma emission of the acceleration process, the observed average frequency of spikes suggests a source density of the order of 3×108 cm–3 consistent with the energy cut-off observed. 相似文献
13.
Woods PM Kouveliotou C van Paradijs J Briggs MS Hurley K Göğüş E Preece RD Giblin TW Thompson C Duncan RC 《The Astrophysical journal》1999,527(1):L47-L50
We present evidence for burst emission from SGR 1900+14 with a power-law high-energy spectrum extending beyond 500 keV. Unlike previous detections of high-energy photons during bursts from soft gamma repeaters (SGRs), these emissions are not associated with extraordinarily bright flares. Not only is the emission hard, but the spectra are better fitted by D. Band's gamma-ray burst (GRB) function rather than by the traditional optically thin thermal bremsstrahlung model. We find that the spectral evolution within these hard events obeys a hardness/intensity anticorrelation. Temporally, these events are distinct from typical SGR burst emissions in that they are longer ( approximately 1 s) and have relatively smooth profiles. Despite a difference in peak luminosity of greater, similar1011 between these bursts from SGR 1900+14 and cosmological GRBs, there are striking temporal and spectral similarities between the two kinds of bursts, aside from spectral evolution. We outline an interpretation of these events in the context of the magnetar model. 相似文献
14.
G. P. Chernov A. A. Stanislavsky A. A. Konovalenko E. P. Abranin V. V. Dorovsky G. O. Rucker 《Astronomy Letters》2007,33(3):192-202
We have performed a comparative analysis of the fine structure of two decametric type II bursts observed on July 17 and August 16, 2002, with the 1024-channel spectrograph of the UTR-2 radio telescope in the frequency range 18.5–29.5 MHz and with the IZMIRAN spectrograph in the frequency range 25–270 MHz. The August 16 burst was weak, ～2–5 s.f.u., but exhibited an unusual fine structure in the form of broadband fibers (Δf e > 250–500 kHz) that drifted at a rate characteristic of type II bursts and consisted of regular narrow-band fibers (Δf e > 50–90 kHz at 24 MHz) resembling a rope of fibers. The July 17 burst was three orders of magnitude more intense (up to 4500 s.f.u. at 20 MHz) and included a similar fiber structure. The narrow fibers were irregular and shorter in duration. They differed from an ordinary rope of fibers by the absence of absorption from the low-frequency edge and by slow frequency drift (slower than that of a type II burst). Both type II bursts were also observed in interplanetary space in the WIND/WAVES RAD2 spectra, but without any direct continuation. Analysis of the corresponding coronal mass ejections (CMEs) based on SOHO/LASCO C2 data has shown that the radio source of the type II burst detected on August 16 with UTR-2 was located between the narrow CME and the shock front trailing behind that was catching up with the CME. The July 17 type II fiber burst also occurred at the time when the shock front was catching up with the CME. Under such conditions, it would be natural to assume that the emission from large fibers is related to the passage of the shock front through narrow inhomogeneities in the CME tail. Resonant transition radiation may be the main radio emission mechanism. Both events are characterized by the possible generation of whistlers between the leading CME edge and the shock front. The whistlers excited at shock fronts manifest themselves only against the background of enhanced emission from large fibers (similar to the continuum modulation in type IV bursts). The reduction in whistler group velocity inside inhomogeneities to 760 km s?1 may be responsible for the unusually low drift rate of the narrow fibers. The magnetic field inside inhomogeneities determined from fiber parameters at 24 MHz is ～0.9 G, while the density should be increased by at least a factor of 2. 相似文献
15.
The height structure of a thick-target solar hard X-ray source is predicted for a beam injected vertically downward with a power-law spectrum and dominated by Coulomb collisional energy losses. This structure is characterised by the ratio of hard X-ray flux from an upper part of the source to that from the entire source, and is essentially a function only of the atmospheric column density ΔN (cm?2) in the upper region. These predictions are compared with the flux ratios at 150 keV and 350 keV observed by two spacecraft for five events in which the solar limb occults part of the source for one spacecraft. In three events the occulting levels h ranged from 0 to 2500 km. For these the theoretical and observed ratios are found to be comparable for values of ΔN in reasonable accord with those found at these altitudes by optical and UV spectroscopic modelling of flare chromospheres. In one event the occultation ratio was observed to rise after the burst peak and it is found that this rise is consistent with an increase in ΔN due to conductively driven chromospheric evaporation. However the energy dependence of the occultation ratio is not consistent with that predicted by the model and it is concluded that non-collisional losses must be significant in beam dynamics. In the other two events, the occultation level h was ? 25 000 km. For these the energy dependence of the occultation ratio is comparable with the model predictions. However the values of ΔN required demand extremely high coronal densities and/or acceleration altitudes. Furthermore, the one observed evolution of the occultation ratio is entirely inconsistent with the model. It is concluded that in these, bremsstrahlung emissions other than that from a beam must be important. 相似文献
16.
P. Démoulin K.-L. Klein C. P. Goff L. van Driel-Gesztelyi J. L. Culhane C. H. Mandrini S. A. Matthews L. K. Harra 《Solar physics》2007,240(2):301-313
Radio emissions of electron beams in the solar corona and interplanetary space are tracers of the underlying magnetic configuration
and of its evolution. We analyse radio observations from the Culgoora and WIND/WAVES spectrographs, in combination with SOHO/LASCO
and SOHO/MDI data, to understand the origin of a type N burst originating from NOAA AR 10540 on January 20, 2004, and its
relationship with type II and type III emissions. All bursts are related to the flares and the CME analysed in a previous
paper (Goff et al., 2007). A very unusual feature of this event was a decametric type N burst, where a type III-like burst, drifting towards
low frequencies (negative drift), changes drift first to positive, then again to negative. At metre wavelengths, i.e., heliocentric distances ≲1.5R
⊙, these bursts are ascribed to electron beams bouncing in a closed loop. Neither U nor N bursts are expected at decametric
wavelengths because closed quasi-static loops are not thought to extend to distances ≫1.5R
⊙. We take the opportunity of the good multi-instrument coverage of this event to analyse the origin of type N bursts in the
high corona. Reconnection of the expanding ejecta with the magnetic structure of a previous CME, launched about 8 hours earlier,
injects electrons in the same manner as with type III bursts but into open field lines having a local dip and apex. The latter
shape was created by magnetic reconnection between the expanding CME and neighbouring (open) streamer field lines. This particular
flux tube shape in the high corona, between 5R
⊙ and 10R
⊙, explains the observed type N burst. Since the required magnetic configuration is only a transient phenomenon formed by reconnection,
severe timing and topological constraints are present to form the observed decametric N burst. They are therefore expected
to be rare features. 相似文献
17.
A specific combination of spectral fine structures in meter – decimeter dynamic spectra of solar radio burst emission is
reported in observations carried out at the Astrophysical Institute Potsdam. We describe and interpret the occurrence of zebra
patterns in fast drifting (type III burst-like) envelopes of absorbed continuum emission. A possible mechanism of the origin
of such an involved spectral pattern is put forward, leading to a necessarily multinonequlibrium component coronal plasma.
The suggested mechanism is based on the fact that during the passage of a fast electron beam through the corona the loss cone
instability (which is caused by electrons captured in a magnetic trap generating the continuum) is quenched. As result, a
fast drift burst appears in absorption, and the zebra pattern becomes visible on the low background emission. This zebra pattern
is generated by a group of electrons with a nonequilibrium distribution over transverse velocities. In the absence of the
beam the pattern is invisible against the background of the stronger continuum. It is shown that the mechanism is sensitive
to the distribution parameters of the different electron ensembles. Therefore the effect in dynamic radio spectra is comparatively
rare but its proper existence underlines that the simultaneous presence of different ensembles of electrons in the flaring
corona can be quite a frequent situation. This can explain some problems in deconvolving X-ray photon spectra to electron
energy spectra. 相似文献
18.
R. D. Robinson 《Solar physics》1985,95(2):343-357
Radial velocities for 144 simple but representative type II bursts were determined from measured frequency time histories. The velocity distribution is peaked in the region between 500 and 700 km s –1 (with the exact value dependent upon the coronal density model assumed) and skewed towards the larger velocities. In 85 % of the cases it was found that the velocities were constant with height. In the remaining 15 % the drift rate decreased drastically at low frequencies. This tended to occur for events having high initial velocities. The measured velocity is dependent upon the properties of the flare event but does not appear to be related to other characteristics of the radio burst. Comparisons show that the group of type II events studied had a velocity distribution which was comparable with that for coronal mass ejection events seen in association with type II bursts. The measured velocities were however statistically smaller than those of interplanetary type II bursts. 相似文献
19.
Alaa I. Ibrahim Hisham Anwer Mohamed H. Soliman Nicholas Mackie-Jones Kalvir S. Dhuga William C. Parke Jean H. Swank Tilan Ukwatta M. T. Hussein T. El-Sherbini 《Astrophysics and Space Science》2007,308(1-4):535-539
A 6.4 keV emission line was discovered in an unusual burst from the soft gamma repeater SGR 1900+14 with the Rossi X-ray Timing
Explorer (RXTE). The line was detected in part of a complex multipeak precursor that preceded the unusual burst of 1998 August
29, i.e. two days after the giant flare of August 27 from the source. The origin of the line was not firmly identified and
two possible interpretations were equally plausible including (a) Kα fluorescence from a small iron rich material that was ejected to the magnetosphere during the August 27 flare, and (b) proton
or α-particle cyclotron resonance. If the iron scenario was correct, we expect to find evidence for the line during the intervening
interval between the flare and the August 29 burst, i.e. on August 28. Here we present the results of the August 28 burst
observation, taken with RXTE. We detect a total of seven bursts whose individual and joint spectra do not show evidence for
spectral lines. We also investigated a sample of nine bursts before and after the August 29 burst (from 1998 June to December)
that do not reveal evidence for a spectral line near 6.4 keV or elsewhere. These results disfavor the iron scenario and make
the proton/α-particle cyclotron resonance interpretation more plausible. The appearance of the emission line in part of a complex burst
and its absence from the studied sample indicate that the line is likely due to a transient phenomenon that may depend on
the burst morphology, energetics and the properties of the emission region.
相似文献
20.
We briefly discuss the observed features including the high flux density, short duration, narrow emission band, fast frequency drift, quasi-periodic oscillation and fast variation of polarized components, of 51 spike emission events observed at 2545/2645 MHz in the solar activity peak year, 1991 January–December, and carry out correlation analysis between these events and optical flares, magnetic field intensity and configuration of flare regions, and sunspot evolution types of active regions. In view of the fact that the observed and statistical characteristics of the spike emissions are very different from those of known types of solar radio burst and known solar radio components, we think that the spike emission in the peak years is probably a new type of radio burst excited by electron cyclotron maser instability under wave-particle resonance, or a new solar radio component. 相似文献