Global Distribution of Electrostatic Electron Cyclotron Harmonic Waves in Saturn's Magnetosphere: A Survey of Over‐13‐Year Cassini RPWS Observations

Abstract

Electron cyclotron harmonic (ECH) waves are electrostatic emissions observed in bands between the harmonics (n) of electron gyrofrequency (f ce ), with dominant wave power centered around (n + 1/2) f ce (e.g.,

Observation of Periodic Rising and Falling Tone ECH Waves at Saturn

“…with the peaking amplitude at   7.7 8.5 L (Long et al, 2021;Menietti et al, 2008Menietti et al, , 2017Tao et al, 2010). The important role of ECH waves in producing Earth's diffuse auroral precipitation has been proposed in previous studies (Horne & Thorne, 2000;Horne et al, 2003;Meredith et al, 2009;Ni et al, 2016;Zhang et al, 2015).…”

“…The averaged amplitudes of Saturnian ECH wave show a pronounced MLT asymmetry, with the nightside amplitude larger than those on the dayside. For the fundamental band, the averaged amplitudes are about 0.01–0.1 mV/m, with the peaking amplitude at (Long et al., 2021; Menietti et al., 2008, 2017; Tao et al., 2010). The important role of ECH waves in producing Earth's diffuse auroral precipitation has been proposed in previous studies (Horne & Thorne, 2000; Horne et al., 2003; Meredith et al., 2009; Ni et al., 2016; Zhang et al., 2015).…”

Efficient Scattering Loss of Energetic Electrons by Enhanced Higher‐Band ECH Waves Observed by Van Allen Probes

“…ECH waves can strongly interact with electrons and significantly affect electron dynamics in the terrestrial magnetosphere (Horne, 2015; Horne & Thorne, 2000), just like other wave modes such as chorus (Guo et al., 2020; He et al., 2021; Jin et al., 2018; S. Liu et al., 2020; Q. Yang et al., 2016), electromagnetic ion cyclotron wave (Guan et al., 2020; C. Yang et al., 2021) and auroral kilometric radiation (Xiao et al., 2022; S. Zhang et al., 2020, 2021). ECH waves generally exhibit banded structures (Fredricks, 1971; Shaw & Gurnett, 1975) with wave power preferentially distributed in the first harmonic band (e.g., Belmont et al., 1983; Long et al., 2021; Lou et al., 2018; Ni et al., 2017; Ni, Thorne, Liang, et al., 2011). Numerous works have demonstrated that the first‐band ECH can be in resonance with electrons at energies of ∼keV, causing the precipitation of diffuse auroral electrons (Fukizawa et al., 2020, 2022; Lou et al., 2021; Ni et al., 2012; Ni, Thorne, Horne, et al., 2011).…”

“…Yang et al, 2016), electromagnetic ion cyclotron wave (Guan et al, 2020; and auroral kilometric radiation (Xiao et al, 2022;. ECH waves generally exhibit banded structures (Fredricks, 1971;Shaw & Gurnett, 1975) with wave power preferentially distributed in the first harmonic band (e.g., Belmont et al, 1983;Long et al, 2021;Lou et al, 2018;Ni et al, 2017;Ni, Thorne, Liang, et al, 2011). Numerous works have demonstrated that the first-band ECH can be in resonance with electrons at energies of ∼keV, causing the precipitation of diffuse auroral electrons (Fukizawa et al, 2020(Fukizawa et al, , 2022Lou et al, 2021;Ni et al, 2012;Ni, Thorne, Horne, et al, 2011).…”

Statistics of Water-group Band Ion Cyclotron Waves in Saturn's Inner Magnetosphere Based on 13 yr of Cassini Measurements

“…Saturnʼs magnetosphere hosts a variety of plasma waves, e.g., whistler-mode waves (Menietti et al 2013(Menietti et al , 2014Woodfield et al 2022), electron cyclotron harmonic (ECH) waves (Tao et al 2010;Menietti et al 2017;Long et al 2021;Teng et al 2021), and Z-mode waves (Ye et al 2009(Ye et al , 2010Menietti et al 2016;Wu et al 2021). Via resonant wave-particle interactions, these waves are recognized to contribute significantly to the local acceleration and loss of Saturnʼs radiation belt electrons (e.g., Menietti et al 2012;Gu et al 2013;Kollmann et al 2018;Woodfield et al 2018Woodfield et al , 2019Yu et al 2019;Yao et al 2021;Woodfield et al 2022).…”