<i>ULYSSES</i>OBSERVATIONS OF MAGNETIC WAVES DUE TO NEWBORN INTERSTELLAR PICKUP IONS. II. APPLICATION OF TURBULENCE CONCEPTS TO LIMITING WAVE ENERGY AND OBSERVABILITY

Cannon, Bradford E.; Smith, Charles W.; Isenberg, Philip A.; Vasquez, Bernard J.; Joyce, Colin J.; Murphy, Neil; Nuno, Raquel G.

doi:10.1088/0004-637x/787/2/133

Cited by 34 publications

(37 citation statements)

References 41 publications

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“…The event is seen when the mean field is 10° from the radial direction. Although not shown here, we have reproduced the analysis of Cannon et al [] which shows that the growth rate for pickup‐ion‐generated waves exceeds the turbulent cascade rate at this time, thereby allowing the wave energy to accumulate.…”

Section: Discussionsupporting

confidence: 80%

“…As a result, the density has fallen to 0.7 p + cm −3 , the average magnetic field is | B | = 4.7 nT and almost radially aligned with Θ B R = 9.6°, and the Alfvén speed is elevated to 123 km s −1 . Past studies [ Joyce et al , ; Cannon et al , , ] have suggested that waves due to newborn interstellar pickup ions are most readily found in rarefaction regions and in other situations where the background turbulence is low.…”

Section: Discussionmentioning

confidence: 99%

“…The development of spectrograms made finding these waves significantly easier. A database of 502 such observations in the Ulysses data was developed from the spectrogram observations and subsequently analyzed [ Smith et al , ; Cannon et al , , , ]. Joyce et al [] reported one observation of He + ‐excited waves in the Voyager data set at 4.5AU.…”

Section: Introductionmentioning

confidence: 99%

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ACE observations of magnetic waves arising from newborn interstellar pickup helium ions

Argall

Fisher

Joyce

et al. 2015

Geophysical Research Letters

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We report low‐frequency magnetic waves that were observed by the Advanced Composition Explorer (ACE) spacecraft on day of year 180 of 1999 with characteristics consistent with the predictions of waves excited by newborn interstellar pickup He+ ions. This event was found by examining daily spectrograms of MAG data, a new data product that is now available to the community via the ACE Science Center. The event shown here is one of approximately 20 similar events that will be analyzed in future studies. This event is fairly typical of those we have found so far. The waves exist at spacecraft‐frame frequencies between the He+ cyclotron frequency and approximately twice the H+ cyclotron frequency. Fluctuations are transverse to the mean magnetic field, are noncompressive, circularly polarized, have field‐aligned minimum variance directions, and are left‐hand polarized in the spacecraft frame as predicted by theory. The event lasts for just under 1 h.

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Section: Discussionsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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ACE observations of magnetic waves arising from newborn interstellar pickup helium ions

Argall

Fisher

Joyce

et al. 2015

Geophysical Research Letters

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“…Magnetic waves due to interstellar pickup ions were first reported as observations by the Ulysses spacecraft, where all 31 events presented were consistent with generation by pickup H + (Murphy et al 1995). A subsequent study revealed 502 events observed by Ulysses, and again all of those waves were excited by pickup H + Cannon et al 2013Cannon et al , 2014aCannon et al , 2014b. An additional event observed by the Voyager 2 spacecraft at 4.5 au reported waves excited by both pickup H + and pickup He + simultaneously ).…”

Section: Introductionmentioning

confidence: 86%

VOYAGER OBSERVATIONS OF MAGNETIC WAVES DUE TO NEWBORN INTERSTELLAR PICKUP IONS: 2–6 au

Aggarwal

Taylor

Smith

et al. 2016

ApJ

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We report observations by the Voyager 1 and 2 spacecraft of low-frequency magnetic waves excited by newborn interstellar pickup ions H + and He + during 1978-1979 when the spacecraft were in the range from 2 to 6.3 au. The waves have the expected association with the cyclotron frequency of the source ions, are left-hand polarized in the spacecraft frame, and have minimum variance directions that are quasi-parallel to the local mean magnetic field. There is one exception to this in that one wave event that is excited by pickup H + is right-hand polarized in the spacecraft frame, but similar exceptions have been reported by Cannon et al. and remain unexplained. We apply the theory of Lee & Ip that predicts the energy spectrum of the waves and then compare growth rates with turbulent cascade rates under the assumption that turbulence acts to destroy the enhanced wave activity and transport the associated energy to smaller scales where dissipation heats the background plasma. As with Cannon et al., we find that the ability to observe the waves depends on the ambient turbulence being weak when compared with growth rates, thereby allowing sustained wave growth. This analysis implies that the coupled processes of pitch-angle scattering and wave generation are continuously associated with newly ionized pickup ions, despite the fact that the waves themselves may not be directly observable. When waves are not observed, but wave excitation can be argued to be present, the wave energy is simply absorbed by the turbulence at a rate that prevents significant accumulation. In this way, the kinetic process of wave excitation by scattering of newborn ions continues to heat the plasma without producing observable wave energy. These findings support theoretical models that invoke efficient scattering of new pickup ions, leading to turbulent driving in the outer solar wind and in the IBEX ribbon beyond the heliopause.

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“…Our recent efforts to continue this study revealed to us a significant error in Table 3 of the published article. Here we correct that table for the sake of future work by ourselves and others.Past analyses of magnetic waves due to newborn interstellar pickup ions observed in interplanetary space have revealed that the waves are most often observed when the background fluctuation levels are low (Cannon et al 2014;Aggarwal et al 2016;Fisher et al 2016). Our recent report of two such wave events observed by the Voyager 2 spacecraft on DOYs 172-174 of 1989 when the spacecraft was at 29.6 au, 3°.…”

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confidence: 79%

Erratum: “Observation of Magnetic Waves Excited by Newborn Interstellar Pickup He⁺ Observed by the Voyager 2 Spacecraft at 30 au” (2017, ApJ, 849, 61)

Argall

Hollick

Pine

et al. 2018

ApJ

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In our published article (Argall et al. 2017), we reported observations of waves due to newborn interstellar pickup He + observed by the Voyager 2 spacecraft at ∼30 au. Our recent efforts to continue this study revealed to us a significant error in Table 3 of the published article. Here we correct that table for the sake of future work by ourselves and others.Past analyses of magnetic waves due to newborn interstellar pickup ions observed in interplanetary space have revealed that the waves are most often observed when the background fluctuation levels are low (Cannon et al. 2014;Aggarwal et al. 2016;Fisher et al. 2016). Our recent report of two such wave events observed by the Voyager 2 spacecraft on DOYs 172-174 of 1989 when the spacecraft was at 29.6 au, 3°. 9 of heliographic latitude, and 205°of heliographic longitude concluded that the these two specific wave events were seen when the background spectrum was dominated by instrument noise. We supported that claim by first analyzing the background spectrum and then comparing it to 14 spectra taken from nearby times when waves were not observed. In that analysis, we computed the spectral index using a spectral fit of the power spectrum, assuming P(f)∼f n . The analysis was performed over two frequency intervals, and then the power at two prescribed frequencies (1 and 10 mHz) was computed using the spectral fits. We showed that when the spectral index of the total power spectrum became shallow (approximately n=−1), the power levels would asymptote to a common value. This value was the lowest value that the spectrum reached throughout the set of spectra studied. We also showed that lowest power level to be consistent with preflight instrument noise tests of the Voyager magnetometer.Unfortunately, there is a critical typographical error in that table. Although the analysis was performed correctly, the two stated frequencies used in the analysis were each an order of magnitude larger than what was actually used. Table 3 of Argall et al. (2017) states that we fit the background power levels at 1 and 10 mHz, when in reality they were fit at 0.1 and 1 mHz. In all other respects, the paper is correct as presented.In the interest of presenting a correct analysis for future citation, we present the corrected table here. In order to provide a more complete and useful analysis, we here present the fit power for 0.1, 1, and 10 mHz.We regret the error and hope it has not caused any confusion.

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ULYSSESOBSERVATIONS OF MAGNETIC WAVES DUE TO NEWBORN INTERSTELLAR PICKUP IONS. II. APPLICATION OF TURBULENCE CONCEPTS TO LIMITING WAVE ENERGY AND OBSERVABILITY

Cited by 34 publications

References 41 publications

ACE observations of magnetic waves arising from newborn interstellar pickup helium ions

ACE observations of magnetic waves arising from newborn interstellar pickup helium ions

VOYAGER OBSERVATIONS OF MAGNETIC WAVES DUE TO NEWBORN INTERSTELLAR PICKUP IONS: 2–6 au

Erratum: “Observation of Magnetic Waves Excited by Newborn Interstellar Pickup He⁺ Observed by the Voyager 2 Spacecraft at 30 au” (2017, ApJ, 849, 61)

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ULYSSESOBSERVATIONS OF MAGNETIC WAVES DUE TO NEWBORN INTERSTELLAR PICKUP IONS. II. APPLICATION OF TURBULENCE CONCEPTS TO LIMITING WAVE ENERGY AND OBSERVABILITY

Cited by 34 publications

References 41 publications

ACE observations of magnetic waves arising from newborn interstellar pickup helium ions

ACE observations of magnetic waves arising from newborn interstellar pickup helium ions

VOYAGER OBSERVATIONS OF MAGNETIC WAVES DUE TO NEWBORN INTERSTELLAR PICKUP IONS: 2–6 au

Erratum: “Observation of Magnetic Waves Excited by Newborn Interstellar Pickup He+ Observed by the Voyager 2 Spacecraft at 30 au” (2017, ApJ, 849, 61)

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Erratum: “Observation of Magnetic Waves Excited by Newborn Interstellar Pickup He⁺ Observed by the Voyager 2 Spacecraft at 30 au” (2017, ApJ, 849, 61)