scispace - formally typeset


About: Chorus is a(n) research topic. Over the lifetime, 829 publication(s) have been published within this topic receiving 8415 citation(s). more


Journal ArticleDOI: 10.1029/JA082I032P05112
Bruce T. Tsurutani1, Edward J. Smith1Institutions (1)
Abstract: The distribution of extremely low frequency (10-1500 Hz) magnetospheric chorus to all local times and latitudes is investigated in order to determine dependence on substorms, and to evaluate the conditions under which chorus is generated. The analysis carefully separates space and time effects by an investigation of data obtained by the OGO 5 search coil magnetometer. A study of spatial dependencies shows that chorus occurs in two magnetic regions: equatorial chorus is located near the equator, and high-latitude chorus is located above 15 degrees. An analysis of chorus in each of the regions illustrates that equatorial chorus is definitely related to substorm, whereas high-latitude chorus often occurs within magnetically quiet intervals. more

Topics: Dawn chorus (76%), Auroral chorus (64%), Chorus (57%) more

386 Citations

Journal ArticleDOI: 10.1016/0032-0633(76)90119-7
W. J. Burtis1, R. A. Helliwell1Institutions (1)
Abstract: Over 400 hours of continuous broadband data obtained by the OGO 3 satellite are analyzed to provide a statistically accurate description of band-limited (magnetospheric) chorus. Certain aspects of the chorus frequency distribution are interpreted in terms of a gyroresonant electron feedback model of generation. An example of high chorus activity during an outbound pass through the noon magnetosphere is examined in detail, the spectral complexity of some chorus is illustrated, and the diurnal variation of chorus occurrence is investigated. The frequency and bandwidth distributions of chorus are analyzed. The results indicate that chorus occurrence depends strongly on local time and dipole latitude, the general region of maximum chorus occurrence approximates the previously reported zone of 'hard' electron precipitation, and the normalized chorus frequency is strongly dependent on dipole latitude. It is shown how a change in the curvature of the whistler-mode refractive-index surface affects focusing of radiation along magnetic field lines and how interference can occur between modes with slightly different ray velocities. It is concluded that most magnetospheric chorus consists of rising emissions which are probably generated by gyroresonant electrons slightly off the equator. more

Topics: Dawn chorus (75%), Auroral chorus (63%), Chorus (56%) more

298 Citations

Open accessBook
01 Jan 1953-
Abstract: The lesser festivals the great or city Dionysia the actors the costumes the chorus the audience the artists of Dionysus. more

Topics: Chorus (54%)

273 Citations

Open accessJournal ArticleDOI: 10.1029/1998GL900071
Abstract: Previous studies have used indirect evidence to argue that whistler-mode chorus emissions are generated near the magnetic equator. In this paper a spatial survey of wave normals and Poynting vectors computed from three-component electric and magnetic field measurements is used to show that chorus is generated very close to the magnetic equator. One surprising result is that there are almost no chorus emissions propagating toward the magnetic equator, such as might be expected from high-latitude magnetospheric reflections. The absence of a reflected component indicates that the chorus is reabsorbed, probably by Landau damping, before returning to the magnetic equatorial plane. more

Topics: Dawn chorus (68%), Auroral chorus (60%), Magnetosphere (55%) more

215 Citations

Journal ArticleDOI: 10.1029/2011JA017035
Abstract: [1] The global distribution of chorus wave amplitudes and their wave normal angles is investigated using high-resolution wave spectra and waveform data from THEMIS for lower-band and upper-band chorus separately. Statistical results show that large amplitude chorus (>300 pT) occurs predominantly from premidnight to postdawn and is preferentially observed at lower L shells ( 50 pT) tend to have wave normal angles of <20° and their wave normal angles become even smaller with increasing wave amplitudes. For modest waves, the wave normal angles are distributed over a broad range with a major peak at <20° and a secondary peak at 60°–80°. Wave normal angles of lower-band chorus are generally smaller on the dayside than on the nightside possibly due to the more uniform and more compressed magnetic field configuration on the dayside. Lower-band chorus becomes more oblique with increasing latitude on the dayside, whereas on the nightside the probability of observing oblique chorus decreases at higher latitudes. Compared to lower-band chorus, the properties of upper-band chorus are somewhat different. Upper-band chorus is considerably weaker in magnetic wave amplitudes, shows tighter confinement to the magnetic equator (<10°), and occurs at smaller L shells (<8). Furthermore, wave normal angles of upper-band chorus are generally larger than those of lower-band chorus, but the occurrence rate still peaks at wave normal angles of <20°, particularly for strong upper-band chorus. more

Topics: Auroral chorus (60%), Chorus (51%)

210 Citations

No. of papers in the topic in previous years

Top Attributes

Show by:

Topic's top 5 most impactful authors

Jacob Bortnik

10 papers, 619 citations

Vassilis Angelopoulos

9 papers, 457 citations

William S. Kurth

9 papers, 268 citations

Craig Kletzing

7 papers, 176 citations

George Hospodarsky

7 papers, 324 citations

Network Information
Related Topics (5)
The arts

29.4K papers, 294.4K citations

77% related

7.1K papers, 90.5K citations

76% related
Musical composition

5.6K papers, 74.8K citations

76% related

3K papers, 70.6K citations

75% related

6.9K papers, 91.6K citations

75% related