Effect of hydromagnetic waves on the lifetime of Van Allen radiation protons

Dragt, Alex J.

doi:10.1029/jz066i006p01641

Cited by 85 publications

(51 citation statements)

References 15 publications

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“…Orthogonal dipolar coordinates, first introduced by Dragt (1961) , are used in the mid-latitude ionosphere because we neglect the thermospheric wind driven by solar extreme ultraviolet (EUV) radiation for simplicity ( Huang and Hill, 1989 ). The ion densities and velocities are calculated from the following continuity and momentum equations:…”

Section: Continuity Momentum and Energy Equationsmentioning

confidence: 99%

Plasma dynamics in Saturn's middle-latitude ionosphere and implications for magnetosphere-ionosphere coupling

Sakai

Watanabe

2016

Icarus

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Section: Continuity Momentum and Energy Equationsmentioning

confidence: 99%

Plasma dynamics in Saturn's middle-latitude ionosphere and implications for magnetosphere-ionosphere coupling

Sakai

Watanabe

2016

Icarus

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“…Violation of the magnetic moment invariant of particles in the geomagnetic field has been studied by DRAGT (1961) andWENTZEL (1961a, b;. Without going into the many interesting details of the calculations, their conclusions may be summarized by noting, after DRAGT, that the most effective hydromagnetic waves are those which are Doppler shifted near the cyclotron frequency of the particle in the frame moving with the particle along the field.…”

Section: Relaxation Of Particle Stressesmentioning

confidence: 99%

Dynamics of the geomagnetic storm

Parker

1962

Space Sci Rev

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This paper is intended as a critical review of current ideas concerning the mechanisms responsible for the geomagnetic storm.The dynamical theory of the geomagnetic storm phenomenon is formulated as a problem in elasticity. The observed variations in the field are the strains produced by particle stresses exerted by gases in interplanetary space, by gases enmeshed in the field, and by the gases in the ionosphere. The stresses exerted by interplanetary gases are principally inward, resulting in the initial phase increase of the horizontal component. The stresses exerted by gases enmeshed in the field are principally outward, resulting in the main phase decrease of the horizontal component. The transient sudden commencement is a hydromagnetic wave phenomenon.The main phase is most simply explained by the shock heating of the ions to key energies at 3 --5 RE during the active phase of the storm. The recovery follows then from charge exchange with the ambient neutral hydrogen. The predicted more rapid recovery at sunspot minimum has been verified observationally.

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“…Energetic protons are n ot trapped 3:~ l.arge distances (i .e. in t he outer zo ne) wh ere ~h e hf~tlLnes ar e probably very short as the r esult of contmuous magnetic distmb an ce~ [Went zel, 1961 ;Dragt, 1961 , andWelch andWhItak er , 1959] . Th e source of these particles , what ever its n atUTe, mllst ther efore b e weak.…”

Section: Energetic Particles In the Magnetospherementioning

confidence: 99%

URSI National Committee Report, XIV General Assembly, Tokyo, September 1963: Commission 4. Magnetospheric Radio (8 Sections)

Bauer¹,

Booker²,

Crichlow³

et al. 1964

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

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CompositionPri01" Lo 1961 it was gener ally accepted tha t the main cons Lituen t of the atmosph er e above 300 km was atomic oxygen up to a n altitude of about 1000 km and that at hi gh er altitudes hydroge n would predominate. Direct ex perim ental evid e nce for th e presen ce of neutral h ydroge n in the outer atmosph er e has come from t he high resolution Ly m an a spectrum obtained by Purcell a nd Tousey [1960]. From th e absorption core of th eir L ym an a spectrum , the total con ten t of hydrogen above the altitude of the rock et measurem ent has b ee n determin ed . John son [1961] has interpreted t his hyd roge n co ntent to be cLi stributed in t he form of n, "geocorona." The problenl of interpretation of the L y man a observations in terms of hydroge n and its location wi th r espect to the earth has r ecently b een r evi ewed in detail b y Donahue [1962]. The computation of the distribution of neutral h ydrogen is complicated by the fact that at magn etospheric levels "exospheri c" conditions prevail, i. e., the mean free path of neutral hydrogen is greater than the local scale height. Because of the escape of particles with high velocities, the velocity distribution is, strictly speaking, non-Maxwellian and the distribution of density with hei gh t does not follow t he simple h ydrostatic equation, but has to be computed by taking into account ballistic escape, b allistic r eentry a nd bound-orbiting particles. Such compu t a.tions have been mad e by bpik and Singer [1961] and by Johnson [1961]. Out to a geocentric distance of a bout two ear th r adii , a simple h y drostatic dis tri bution , however , stillreprese n ts fI, r easonably good n.p pro xi III ation .Photoionization and /or ch ar ge exchange with oxygen ion s of the neu tral hyd rogen of th e geocoron a lead to the protons constituting t h e " protonosph er e." rrhe ions fLt J1h1gn etospheric levels are distribu ted according t? a diffu siv e equilibrium distribution , i.e., hydrostatIcally supported bu t constrain ed by the ~arth 's magn etic field. For ions the m ean fr ee pn.th l S short enough so that the concep t of an ionexosphere is not applicable [Johnson , 1962] . While the diffusive equilibriurn distribution of an ionic sp ecies ,~as gen~]"ally con~id ered to be go:v:erned by a scale h eJght t WICe t hat of t h e cOl"l"espondmg neutral sp ecies, it was pointed out by Mange [1960Mange [ 1961] that t his con cept is not justified for a minor ' ion in tbe presen ce of other ions. The electric field which is set up to prevent further charge separation ' of electrons and ions diffu sing under gravity, and which is propor tional to t h e me}1n mass of the (s ingly charged) positive ions, ca uses the density of minor ligh t ions first to increase with alt it ud e until it b eco mes predominant, n.Iter whi ch it shows the llsual expon ential decrease with altitude according to n. scn.le h eigh t appr~aching twice that of t he conesponding n eutral constItu ent. S ubsequently to . Mange's independent derivation of the equation go...

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Effect of hydromagnetic waves on the lifetime of Van Allen radiation protons

Cited by 85 publications

References 15 publications

Plasma dynamics in Saturn's middle-latitude ionosphere and implications for magnetosphere-ionosphere coupling

Plasma dynamics in Saturn's middle-latitude ionosphere and implications for magnetosphere-ionosphere coupling

Dynamics of the geomagnetic storm

URSI National Committee Report, XIV General Assembly, Tokyo, September 1963: Commission 4. Magnetospheric Radio (8 Sections)

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