Outline > does the presence of NL waves affect the conclusion that QL acceleration suffices? > it...
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![Page 1: Outline > does the presence of NL waves affect the conclusion that QL acceleration suffices? > it depends... Outline Large amplitude whistler waves Limitations.](https://reader035.fdocuments.net/reader035/viewer/2022070400/56649f005503460f94c16339/html5/thumbnails/1.jpg)
Outline
> does the presence of NL waves affect the conclusion that QL acceleration suffices?> it depends...
Outline• Large amplitude whistler waves• Limitations for NL wave-particle interactions
• spatial scales of whistler waves: coherence and source region scale
• Large amplitude oblique waves and peculiarities for NL wave-particle interactions
• Discussion & Conclusions
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![Page 2: Outline > does the presence of NL waves affect the conclusion that QL acceleration suffices? > it depends... Outline Large amplitude whistler waves Limitations.](https://reader035.fdocuments.net/reader035/viewer/2022070400/56649f005503460f94c16339/html5/thumbnails/2.jpg)
Large amplitude whistlers
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Magnetic and electric field data from Van Allen Probe B
![Page 3: Outline > does the presence of NL waves affect the conclusion that QL acceleration suffices? > it depends... Outline Large amplitude whistler waves Limitations.](https://reader035.fdocuments.net/reader035/viewer/2022070400/56649f005503460f94c16339/html5/thumbnails/3.jpg)
Occurrence rate fo large amplitude whistlers
The occurrence rate of large amplitude chorus type whistler waves. Occurrence rate for the waves with averaged magnetic field amplitudes Bw > 100 pT (means ~5-10 times larger) are indicated by red circles. The occurrence rate for waves, with average magnetic field amplitudes Bw > 10 pT are indicated by black circles. Panels b and c present the distribution of the occurrence rate of Bw > 100 pT waves in the L-shell/MLT frame for two ranges of Kp S
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![Page 4: Outline > does the presence of NL waves affect the conclusion that QL acceleration suffices? > it depends... Outline Large amplitude whistler waves Limitations.](https://reader035.fdocuments.net/reader035/viewer/2022070400/56649f005503460f94c16339/html5/thumbnails/4.jpg)
The schematic illustration of Bw magnetic field perturbation structure in a vicinity of the wave source. Red/blue color indicates the amplitude of Bw. Yellow arrows shows directions of wave normal for different wave packets.
Wave transverse spatial scales
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Magnetic field from Van Allen Probe A and B close approach event
![Page 5: Outline > does the presence of NL waves affect the conclusion that QL acceleration suffices? > it depends... Outline Large amplitude whistler waves Limitations.](https://reader035.fdocuments.net/reader035/viewer/2022070400/56649f005503460f94c16339/html5/thumbnails/5.jpg)
Spectrograms of magnetic field fluctuations captured aboard four THEMIS spacecraft. Panels (from top to bottom) show data from THB, THC, THD, and THE [Agapitov et al., 2010]
Coherence scales for chorus
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Source region size ~ 3000 km at L~9~600 km at L~4-5
Coherence scale ~300 km at L~9 ~70-80 km at L~4-5
[Agapitov et al., 2010, 2011]
Coherence Scale << Chorus Source Scale even in a vicinity of the equator
![Page 6: Outline > does the presence of NL waves affect the conclusion that QL acceleration suffices? > it depends... Outline Large amplitude whistler waves Limitations.](https://reader035.fdocuments.net/reader035/viewer/2022070400/56649f005503460f94c16339/html5/thumbnails/6.jpg)
Cattel et al. 2008 GRL
Wilson et al. 2011 GRL
Cully et al. 2008 GRL
Large amplitude oblique whistlers
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![Page 7: Outline > does the presence of NL waves affect the conclusion that QL acceleration suffices? > it depends... Outline Large amplitude whistler waves Limitations.](https://reader035.fdocuments.net/reader035/viewer/2022070400/56649f005503460f94c16339/html5/thumbnails/7.jpg)
Large amplitude whistlers
The critical wave amplitude is shown as a function of pitch-angle for several energies and three sets of system parameters [Artemyev et al., 2014]
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log 1
0(in
itial
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in k
eV)
equatorial pitch-angle equatorial pitch-angleenergy gain in keV
100 keV 100 keV
Landau resonance Cyclotron resonance
Energy gain for a single trapping (time scale of such trapping is less than 1/4 of bounce period) is shown for two resonances as function of initial energy (vertical axis) and initial equatorial pitch-angle (horizontal axis). Particles with initial ~100 keV are indicated by horizontal red lines.
![Page 8: Outline > does the presence of NL waves affect the conclusion that QL acceleration suffices? > it depends... Outline Large amplitude whistler waves Limitations.](https://reader035.fdocuments.net/reader035/viewer/2022070400/56649f005503460f94c16339/html5/thumbnails/8.jpg)
Chorus Energy Budget
Distribution of the energy of whistler waves in the Earth radiation belts. The distribution of the density of whistler wave energy W (in mV2m2) is displayed in the (L, l) space. Data are shown for two ranges of magnetic latitude (the near-equator region with |l| in [0,20] and the high latitude region with |l| in [20,40]), for day and night sectors, and for low (Kp<3) and high (Kp>3) geomagnetic activity [Artemyev et al., Nature Communication 2015]. S
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![Page 9: Outline > does the presence of NL waves affect the conclusion that QL acceleration suffices? > it depends... Outline Large amplitude whistler waves Limitations.](https://reader035.fdocuments.net/reader035/viewer/2022070400/56649f005503460f94c16339/html5/thumbnails/9.jpg)
Summary
• Large amplitudes wave are regularly observed during perturbed geomagnetic conditions (occurrence rate >10% for certain locations)
• The significant part of whistler waves energy is contained in oblique waves and global energy budget is dramatically underestimated if the parallel waves approach is used
• Decrease of the amplitude threshold (as well as particles energy treshold) for NL interactions
• Nonlinear trapping (and acceleration) is limited by losing of the phase coherence for waves propagating in a randomly inhomogeneous plasmas - necessary to quantify for the cyclotron and Landau resonances! -> wave amplitude is not the single parameter to test the applicability conditions for QL and NL approaches S
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