Reply to Comment by Lamy et al. on “Locating the source field lines of Jovian decametric radio emissions”

Abstract

Locating the source of decametric (DAM) radio emissions is a key step in the use of remote radio observations to understand the Jovian magnetospheric dynamics and their interaction with the planet's moons. Wang YM et al. (2020) presented a method by which recorded arc-shaped DAM emissions in the radio dynamic spectra can be used to locate the source of a DAM. An Io-related DAM event on March 14, 2014 was used to demonstrate the method. A key parameter in the method is whether the DAM is emitted in the northern or the southern hemisphere; the hemisphere of origin can be determined definitively from the polarization of the emission. Unfortunately, polarization information for the emission on March 14, 2014 event was not recorded. Our analysis assumed the source to be in the northern hemisphere. Lamy et al. ( 2022) argue convincingly that the source was probably in the southern hemisphere. We appreciate the helpful contribution of Lamy et al. (2022) to this discussion and have updated our analysis, this time assuming that the DAM source was in the southern hemisphere. We also explore the sensitivity of our method to another parameter -the height at which the value of f ce,max , which is the maximal electron cyclotron frequency reached along the active magnetic flux tube, is adopted. Finally, we introduce our recent statistical study of 68 DAM events, which lays a more solid basis for testing the reliability of our method, which we continue to suggest is a promising tool by which remote radio observations can be used to locate the emission source of Jovian DAMs.

Determining the Beaming of Io Decametric Emissions: A Remote Diagnostic to Probe the Io‐Jupiter Interaction

“…Unfortunately, the authors applied it to a single Io‐DAM event observed by Wind and STEREO A/B waves instruments, erroneously identified as an Io‐B emission instead of an Io‐D one (Lamy et al., 2022). The correction of the hemisphere of origin in turn yields larger θ ( f ) ∼ 72 − 65° and lower E e − ∼ 5 − 9 keV (Wang et al., 2022), in excellent agreement with our results summarized in Figure 11. The correction brought by Wang et al.…”

“…The correction brought by Wang et al. (2022) also illustrated that a misidentification of the Io‐DAM hemisphere yielded in their case a systematic error up to −7° on θ and +9 keV on E e − .…”

Determining the beaming of Io decametric emissions : a remote diagnostic to probe the Io-Jupiter interaction

“…The correction of the hemisphere of origin in turn yields larger θ(f ) ∼ 72 − 65 • and lower E e− ∼ 5 − 9 keV (Wang et al, 2022), in excellent agreement with our results summarized in Figure 11. The correction brought by (Wang et al, 2022) also illustrated that a misidentification of the Io-DAM hemisphere yielded in their case a systematic error up to −7 • on θ and +9 keV on E e− . Martos et al (2020) developed a different method, applied to one example of Io-A, B, C and D events (sometimes made of multiple arcs) as observed by Juno/Waves alone.…”

“…Unfortunately, the authors applied it to a single of Io-DAM event observed by Wind and STEREO A/B waves instruments, erroneously identified as an Io-B emission instead of an Io-D one (Lamy et al, 2022). The correction of the hemisphere of origin in turn yields larger θ(f ) ∼ 72 − 65 • and lower E e− ∼ 5 − 9 keV (Wang et al, 2022), in excellent agreement with our results summarized in Figure 11. The correction brought by (Wang et al, 2022) also illustrated that a misidentification of the Io-DAM hemisphere yielded in their case a systematic error up to −7 • on θ and +9 keV on E e− .…”

Determining the beaming of Io decametric emissions, a remote diagnostic to probe the Io-Jupiter interaction

“…Unfortunately, the authors applied it to a single Io-DAM event observed by Wind and STEREO A/B waves instruments, erroneously identified as an Io-B emission instead of an Io-D one (Lamy et al, 2022). The correction of the hemisphere of origin in turn yields larger θ(f) ∼ 72 − 65° and lower E e− ∼ 5 − 9 keV (Wang et al, 2022), in excellent agreement with our results summarized in Figure 11. The correction brought by Wang et al (2022) also illustrated that a misidentification of the Io-DAM hemisphere yielded in their case a systematic error up to −7° on θ and +9 keV on E e− .…”