Fundamentals of very low frequency emission generation mechanisms

Brice, Neil

doi:10.1029/jz069i021p04515

Cited by 216 publications

(117 citation statements)

References 31 publications

Supporting

Mentioning

114

Contrasting

Unclassified

Order By: Relevance

“…Most theories of such emissions have centered around two resonances which are known to e>-..'ist in the i.nteraction of energetic particles with a stationary magneto active plasma [Brice, 1964]. In these resonances an EM wave is generated or amplified in the ftmbient plasma at a frequency which , due to tbe doppler affect, appears to the particles of the stream ftS zero frequency or the particle gyrofrequency.…”

Section: Discussionmentioning

confidence: 99%

VLF noise bands observed by the alouette I satellite

Belrose¹,

Barrington²

1965

J. RES. NATL. BUR. STAN. SECT. D. RAD. SCI.

View full text Add to dashboard Cite

Alouette I o bser vations of VLF ionospheric noise or hiss have r evealed so me interesting f eatures of such noises w hen r eceived within or a bove the ionosphere. In addition to emission ba nds whose fr equencies a rc relatively independ ent of posit ion , or va ry sporad ically wit h position , t h e sat ellite oft en sees an emission band (o r bands) wit h a well defin ed lower frequency that increases with d ee reasin g magnet ic latitude o f the sat elli t e. On occas ion imila r emissions a rc " trigger ed " or en ha nced by sho rt and long fr act io nal hop whistlers propagating p as t t he satell ite, which places t he ge neration reg io n i n t he vicinity of the satelli te. The most regul a r noise ban ds a rc fo und in a rather narrow zone defined b y magnet ic L values between 2 .. 5 and 4, in va ri a nt magnetic lat it udes 50 to 60°, but ba nds with a stron ger dependence on the magnetic fi eld a rc so metimes found at hi g hcr latitudes.Obser vation s duri ng full sweeps of t he sat elli te across t he magnetic eq uato r have r evealed t ha t the vari a ble freq uency band seen in the No rt hern H emi sphere can sometim es be rep eated at almost exactly co rres pondin g L va lues in the South e rn H emi sphere. At the t ime o f major noise sto r ms, t he a uroral zone is so metimes weil defin ed by the obser va t ions, as lyin g between L values of 4 to 9, magnet ic latitud es 60 to 70°.It is not possible at p rese nt to give a ny fin al ex pla natio n o f t hese noise bands , but certain of their features a re di scussed in t he li ght of current theories of t he ge nerat ion of VLF ionospheri c no ise. . IntroductionBursts of VLF ionospheric noise or " hiss," which occur in the a udio frequency range 0.1 to 15 k c/s, and last for p eriods ranging from sever al minutes to a few h ours, bave b een studied at DRTE and elsewhere [Ellis, 1959] and Watts et al. [1963], for several years. Hiss occurs in broad b ands or in one or more n arrow bands. Tbe narr ow bands often h ave b andwid ths of 1 k c/s or less. The most common t ype, " isolated bursts," is ty pical of magn etically quiet conditions. These are also som etimes associated with isolated magn etic b ays, and ionosph eric radio wave ab sorption. A second type oceurs as an extended seri es of hiss bursts or noise s torms. All m a jor magnetic storms are accompanied b y noise storms. Hiss h as been correlated with airglow [Duncan and E llis, 1959], with aurora [Martin e t al. , 1960], and with abnormal D -region absorption [\Vatts et al. , 1963] .Although the ground observations have r evealed much information on the occurrence of the hiss bursts, there are difficulties in interpreting de tailed studies of their char acteristics. This is partly b ecause iono spheric attenuation affects the noise intensities observed by a ground-based receiver, and p artly becau se prop agation under tbe ionosphere allows observation of h iss generated in a wide range of magnetic latitudes. The effects of the lower ionosphere on the prop agation of VLF emiss...

show abstract

Section: Discussionmentioning

confidence: 99%

VLF noise bands observed by the alouette I satellite

Belrose¹,

Barrington²

1965

J. RES. NATL. BUR. STAN. SECT. D. RAD. SCI.

View full text Add to dashboard Cite

show abstract

“…Field-aligned focusing of ray paths (by ducts or special features of the refractive index surface) are also thought to play an important role (Burtis and Helliwell, 1975 and Helliwell, 1969) has now been confirmed by Poynting flux measurements (LeDocq et al, 1998), which show that the source is located very close to the magnetic equator. The exact reason for the highly coherent discrete frequency-time structure is poorly understood, although the frequency variations are likely to be due to a combination of the inhomogeneous nature of the medium and the nonlinear interaction that arises when resonant electrons are trapped by the magnetic field of the wave (Brice, 1962(Brice, , 1964Helliwell, 1967;Nunn et al, 1997). Chorus emissions are thought to drive electron precipitation in the subauroral regions outside the plasmapause and are sometimes directly controlled by the solar wind dynamic pressure (Lauben et al, 1998;Salvati et al, 2000).…”

Section: Chorusmentioning

confidence: 99%

First results from the Cluster wideband plasma wave investigation

et al. 2001

View full text Add to dashboard Cite

Abstract. In this report we present the first results from the Cluster wideband plasma wave investigation. The four Cluster spacecraft were successfully placed in closely spaced, high-inclination eccentric orbits around the Earth during two separate launches in July -August 2000. Each spacecraft includes a wideband plasma wave instrument designed to provide high-resolution electric and magnetic field waveforms via both stored data and direct downlinks to the NASA Deep Space Network. Results are presented for three commonly occurring magnetospheric plasma wave phenomena: (1) whistlers, (2) chorus, and (3) auroral kilometric radiation. Lightning-generated whistlers are frequently observed when the spacecraft is inside the plasmasphere. Usually the same whistler can be detected by all spacecraft, indicating that the whistler wave packet extends over a spatial dimension at least as large as the separation distances transverse to the magnetic field, which during these observations were a few hundred km. This is what would be expected for nonducted whistler propagation. No case has been found in which a strong whistler was detected at one spacecraft, with no signal at the other spacecraft, which would indicate ducted propagation. Whistler-mode chorus emissions are also observed in the inner region of the magnetosphere. In contrast to lightninggenerated whistlers, the individual chorus elements seldom show a one-to-one correspondence between the spacecraft, indicating that a typical chorus wave packet has dimensions transverse to the magnetic field of only a few hundred km or less. In one case where a good one-to-one correspondence existed, significant frequency variations were observed between the spacecraft, indicating that the frequency of the wave packet may be evolving as the wave propagates. Auroral kilometric radiation, which is an intense radio emission generated along the auroral field lines, is frequently observed over the polar regions. The frequency-time structure of this radiation usually shows a very good one-to-one correspondence between the various spacecraft. By using the Correspondence to: D. A. Gurnett (donald-gurnett@uiowa.edu) microsecond timing available at the NASA Deep Space Network, very-long-baseline radio astronomy techniques have been used to determine the source of the auroral kilometric radiation. One event analyzed using this technique shows a very good correspondence between the inferred source location, which is assumed to be at the electron cyclotron frequency, and a bright spot in the aurora along the magnetic field line through the source.

show abstract

“…Gyration, bounce, and drift frequencies of different L-shell ranges are marked. The ULF wave frequency range overlaps the bounce and drift frequencies of electrons and ions in the inner magnetosphere, indicating that bounce and drift resonance involving these waves is possible In general, inner-magnetosphere wave-particle interactions are affected by VLF waves (Brice 1964;Kennel and Petschek 1966;Lyons and Thorne 1970;Lyons et al 1972;Abel and Thorne 1998a, b) and ULF waves Kivelson 1981, 1982;Mathie and Mann 2001;O'Brien et al 2003). Wave-particle interactions involving ULF waves are discussed in Sect.…”

Section: Introductionmentioning

confidence: 99%

The interaction of ultra-low-frequency pc3-5 waves with charged particles in Earth’s magnetosphere

Zong

Rankin

Zhou

2017

Rev. Mod. Plasma Phys.

140

162

View full text Add to dashboard Cite

One of the most important issues in space physics is to identify the dominant processes that transfer energy from the solar wind to energetic particle populations in Earth's inner magnetosphere. Ultra-low-frequency (ULF) waves are an important consideration as they propagate electromagnetic energy over vast distances with little dissipation and interact with charged particles via drift resonance and drift-bounce resonance. ULF waves also take part in magnetosphereionosphere coupling and thus play an essential role in regulating energy flow throughout the entire system. This review summarizes recent advances in the characterization of ULF Pc3-5 waves in different regions of the magnetosphere, including ion and electron acceleration associated with these waves.

show abstract

Fundamentals of very low frequency emission generation mechanisms

Cited by 216 publications

References 31 publications

VLF noise bands observed by the alouette I satellite

VLF noise bands observed by the alouette I satellite

First results from the Cluster wideband plasma wave investigation

The interaction of ultra-low-frequency pc3-5 waves with charged particles in Earth’s magnetosphere

Contact Info

Product

Resources

About