Phase-matching enhanced ion heating by nonresonant Alfvén waves

2012 ◽  
Vol 19 (7) ◽  
pp. 072118 ◽  
Author(s):  
Kehua Li ◽  
Xueyu Gong ◽  
Xingqiang Lu ◽  
Wei Guo ◽  
Xinxia Li
1983 ◽  
Vol 25 (9) ◽  
pp. 1021-1035 ◽  
Author(s):  
A De Chambrier ◽  
A Heym ◽  
F Hofmann ◽  
B Joye ◽  
R Keller ◽  
...  

2020 ◽  
Vol 27 (1) ◽  
pp. 012901
Author(s):  
Jiansheng Yao ◽  
Quanming Lu ◽  
Xinliang Gao ◽  
Jian Zheng ◽  
Huayue Chen ◽  
...  

2008 ◽  
Vol 684 (2) ◽  
pp. L119-L122 ◽  
Author(s):  
Sofiane Bourouaine ◽  
Eckart Marsch ◽  
Christian Vocks

2020 ◽  
Author(s):  
David Knudsen

<p>The Thermal Ion Imagers on Swarm A-C, and the Suprathermal Electron/Ion Imager on ePOP (now “Swarm-E”) provide a unique view of charged particle distribution functions in the ionosphere at high time resolution (up to 100 images/s). Through high resolution, CCD-based imaging (~3000 pixels/image), ion drift velocity is derived from these images at a resolution of 20 m/s or better, and in general agreement with velocities derived from ground based radars [1] and an empirical convection model [2]. This talk reviews recent scientific applications of this technique, which are wide-ranging and include mechanisms of ion heating and upflow [3,4], M-I coupling via Alfven waves [5,6], electron acceleration and heating by Alfven waves [7,8, 9], intense plasma flows associated with “Steve” [10,11], and electrodynamics of large-scale FAC systems[ 12], among others. In addition, future opportunities made possible by these data will be discussed.</p><p>[1] Koustov et al. (2019), JGR, https://doi.org/10.1029/2018JA026245</p><p>[2] Lomidze et al. (2019), ESS, https://doi.org/10.1029/2018EA000546</p><p>[3] Shen and Knudsen (2020a), On O+ ion heating by BBELF waves at low altitude, JGR, in revision.</p><p>[4] van Irsel et al. (2020), Highly correlated ion upflow and electron temperature variations in the high latitude topside ionosphere, submitted to JGR.</p><p>[5] Pakhotin et al. (2020), JGR, https://doi.org/10.1029/2019JA027277</p><p>[6] Wu et al. (2020a), Swarm survey of Alfvenic fluctuations and their relation to nightside field-aligned current and auroral arcs systems, JGR, in revision.</p><p>[7] Liang et al. (2019), JGR, https://doi.org/10.1029/2019JA026679</p><p>[8] Wu et al. (2020b), e-POP observations of suprathermal electron bursts in the ionospheric Alfven resonator, GRL, submitted.  </p><p>[9] Shen and Knudsen (2020b), Suprathermal electron acceleration perpendicular to the magnetic field in the topside ionosphere, JGR, in press.</p><p>[10] Archer et al. (2019), JGR, https://doi.org/10.1029/2019GL082687</p><p>[11] Nishimura et al. (2019), JGR, https://doi.org/10.1029/2019GL082460</p><p>[12] Olifer et al (2020), Swarm observations of dawn/dusk asymmetries between Pedersen conductance in upward and downward FAC regions, submitted to JGR.</p><p> </p>


2018 ◽  
Vol 859 (2) ◽  
pp. 120 ◽  
Author(s):  
Huayue Chen ◽  
Xinliang Gao ◽  
Quanming Lu ◽  
Shui Wang

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
D. F. Escande ◽  
V. Gondret ◽  
F. Sattin

Abstract Ion heating by Alfvén waves has been considered for long as the mechanism explaining why the solar corona has a temperature several orders of magnitude higher than the photosphere. Unfortunately, as the measured wave frequencies are much smaller than the ion cyclotron frequency, particles were expected to behave adiabatically, impeding a direct wave-particle energy transfer to take place, except through decorrelating stochastic mechanisms related to broadband wave spectra. This paper proposes a new paradigm for this mechanism by showing it is actually much simpler, more general, and very efficient. Indeed, for measured wave amplitudes in the quiet corona, ion orbits are shown to cross quasi-periodically one or several slowly pulsating separatrices in phase space. Now, a separatrix is an orbit with an infinite period, thus much longer than the pulsation one. Therefore, each separatrix crossing cancels adiabatic invariance, and yields a very strong energy transfer from the wave, and thus particle heating. This occurs whatever be the wave spectrum, even a monochromatic one. The proposed mechanism is so efficient that it might lead to a self-organized picture of coronal heating: all Alfvén waves exceeding a threshold are immediately quenched and transfer their energy to the ions.


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