Energetic proton precipitation related to ion–cyclotron waves

Yahnin, A. G.; Yahnina, T. A.

doi:10.1016/j.jastp.2007.02.010

Cited by 106 publications

(103 citation statements)

References 54 publications

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“…The generation of the EMIC waves and the wave scattering efficiency are known to be sensitive to the cold plasma distribution, and the associated detached proton precipitation regions are known to be observed near the plasmapause location (Yahnin and Yahnina, 2007). To characterize the plasmapause position we looked through the variation in the spacecraft potential along the THEMIS trajectories.…”

Section: A Sergeev Et Al: Isotropy Boundary Conditionsmentioning

confidence: 99%

“…An association between EMIC waves and proton precipitation (often isotropic) is easier to establish for the detached precipitation structures (Yahnin and Yahnina, 2007) than for the isotropy boundary case. Liang et al (2014) analyzed numerous cases of the inverse proton energy dispersion of low-energy (1-20 keV) protons, provided their theoretical explanation, and showed a couple of cases in which EMIC waves were directly observed in the equatorial magnetosphere in the sector where the inverse IB dispersion was identified.…”

Section: Introductionmentioning

confidence: 99%

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Magnetospheric conditions near the equatorial footpoints of proton isotropy boundaries

et al. 2015

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Abstract. Data from a cluster of three THEMIS (Time History of Events and Macroscale Interactions during Substorms) spacecraft during February-March 2009 frequently provide an opportunity to construct local data-adaptive magnetospheric models, which are suitable for the accurate mapping along the magnetic field lines at distances of 6-9 Re in the nightside magnetosphere. This allows us to map the isotropy boundaries (IBs) of 30 and 80 keV protons observed by low-altitude NOAA POES (Polar Orbiting Environmental Satellites) to the equatorial magnetosphere (to find the projected isotropy boundary, PIB) and study the magnetospheric conditions, particularly to evaluate the ratio K IB (R c /r c ; the magnetic field curvature radius to the particle gyroradius) in the neutral sheet at that point. Special care is taken to control the factors which influence the accuracy of the adaptive models and mapping. Data indicate that better accuracy of an adaptive model is achieved when the PIB distance from the closest spacecraft is as small as 1-2 Re. For this group of most accurate predictions, the spread of K IB values is still large (from 4 to 32), with the median value K IB ∼ 13 being larger than the critical value K cr ∼ 8 expected at the inner boundary of nonadiabatic angular scattering in the current sheet. It appears that two different mechanisms may contribute to form the isotropy boundary. The group with K ∼ [4, 12] is most likely formed by current sheet scattering, whereas the group having K IB ∼ [12, 32] could be formed by the resonant scattering of low-energy protons by the electromagnetic ion-cyclotron (EMIC) waves. The energy dependence of the upper K limit and close proximity of the latter event to the plasmapause locations support this conclusion.We also discuss other reasons why the K ∼ 8 criterion for isotropization may fail to work, as well as a possible relationship between the two scattering mechanisms.

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Section: A Sergeev Et Al: Isotropy Boundary Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Magnetospheric conditions near the equatorial footpoints of proton isotropy boundaries

et al. 2015

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“…In fact, there is still much current interest in ion pitch angle scattering by EMIC waves in the context of ring current dynamics. This is evidenced by the substantial literature that relates EMIC waves to ion precipitation resulting in ring current decay [e.g., Cornwall et al, 1970;Erlandson and Ukhorskiy, 2001;Summers, 2005;Fraser et al, 2006;Jordanova et al, 2007;Yahnin and Yahnina, 2007;Engebretson et al, 2008;Sakaguchi et al, 2008;Spasojevic et al, 2011;Xiao et al, 2012;Yuan et al, 2014]. In the present work, we treat EMIC wave-ion interactions as linear or quasi-linear, in common with most previous studies.…”

Section: Introductionmentioning

confidence: 93%

Limitation of energetic ring current ion spectra

Summers

Shi

2015

JGR Space Physics

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We address the problem of determining the limiting energetic ring current ion spectrum resulting from electromagnetic ion cyclotron (EMIC)‐wave‐ion interactions. We solve the problem in a relativistic regime, incorporating a cold background multi‐ion plasma component and without assuming a predetermined form for the ion energy distribution. The limiting (Kennel‐Petschek) spectrum is determined by the condition that the EMIC waves acquire a specified gain over a given convective length scale for all frequencies over which wave growth occurs. We find that the limiting ion spectrum satisfies an integral equation that must be solved numerically. However, at large particle energy E, the limiting spectrum takes the simple form J ∝ 1/E, E → ∞. Moreover, this 1/E spectral shape does not depend on the energetic ion in question nor on the background multi‐ion plasma composition. We provide numerical solutions for the limiting spectra for Earth‐like parameters. In addition, at four planets, Jupiter, Saturn, Uranus, and Neptune, we compare measured ion spectra with corresponding numerical limiting spectra. This paper parallels an earlier analogous study on the limitation of radiation belt electron spectra by whistler mode wave‐electron interactions.

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“…We did not take into account, for example, that simultaneous precipitation of protons into the ionosphere can change the quantitative parameters of the ionosphere, which can lead to a change in the frequency of transmission of the frequency range through the ionospheric Alven resonator over time [Mursula at al., 2000;Yahnin at al., 2007]. Conclusions 1.…”

Section: Fig 5 (A)-pc1 Spectrogram At Nur (B)-psw Variationsmentioning

confidence: 99%

Book of Proceedings Tenth Workshop Primorsko, Bulgaria 2018

Danov¹,

Georgieva²,

Kirov³

2018

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IIn ns st tr ru um me en nt ta at ti io on n f fo or r S Sp pa ac ce e W We ea at th he er r D Da at ta a P Pr ro oc ce es ss si in ng g a an nd d M Mo on ni it to or ri in ng g Sadovnichii V.A., Panasyuk M.I., Lipunov V.M., Bogomolov A.V., Bogomolov V.V. et.al. Monitoring of space radiation and other hazards in multi-satellite project `Universat-SOCRAT 123 S. Yerin, A. Stanislavsky, I. Bubnov, A. Konovalenko, P. Tokarsky, V. Zakharenko Small-sized radio telescopes for monitoring and studies of solar radio emission at meter and decameter wavelengths 129 M.M. Kalinichenko, O.O. Konovalenko, A.I. Brazhenko, N.V Šterc, D. Roša, D. Maričić, D. Hržina, I. Romštajn, A. Chilingarian, T. Karapetyan, D. Cafuta, M. Horvat Abstract.A powerful series of solar flares is occurred in the minimum of solar activity 2017 September 4 -11 over the active region AR12673. This active region produces two large and many small flares. The flare X8.2 is followed by solar cosmic rays. The active region at that time is situated on the back side of the Sun disk behind the Western limb. The front of the accelerated protons flux arrives to the Earth with the delay not exceeding the proton flight time from the Sun. Such proton propagation can occur only along the lines of the interplanetary magnetic field. There is no reason to believe that the mechanisms of cosmic ray acceleration on the Sun and other stars are of different nature. The flux of relativistic electrons does not show any connection with the solar cosmic rays. The results of SDO spacecraft are used to study the pre-flare state and flare development. The source of flare radiation in the spectral lines of the highly ionized irons FeXXIV and FeXXIII is observed in the corona. The emission of these spectral lines sharp increases during flare X-ray radiation appearing. The energy release of a flare occurs in the corona above an active region. The temperature in the flare is greater than 20 MK. The size of the hot plasma cloud is ~10 10 cm. IntroductionThe solar constant indicates an amazing stability of the solar thermonuclear reactor. The solar constant is 1367 W/m 2 . The change of the solar constant during the 11-year cycle of solar activity does not exceed ~10 -3 . Against the backdrop of this amazing stability of the Sun's work the big solar flares are observed several times per a year. The flare energy release takes place in the corona over a complex active region with a magnetic flux greater than 10 22Mx. The energy of a solar flare can exceed 10 32 erg. The flare duration is from 10 to 100 minutes. The flare is a manifestation of a number of physical processes, including X-ray radiation, the ejection of the corona substance and proton acceleration to the relativistic energy of not less than 20 GeV [Balabin et al., 2005; Podgorny and Podgorny, 2016].The Sun is the only astronomical object that generates proton pulses with the relativistic energy. The solar proton acceleration takes place along a singular line of the current sheet above an active region. The electric ...

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Energetic proton precipitation related to ion–cyclotron waves

Cited by 106 publications

References 54 publications

Magnetospheric conditions near the equatorial footpoints of proton isotropy boundaries

Magnetospheric conditions near the equatorial footpoints of proton isotropy boundaries

Limitation of energetic ring current ion spectra

Book of Proceedings Tenth Workshop Primorsko, Bulgaria 2018

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