the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
An Overview of Solar Radio Type II Bursts through analysis of associated solar and near Earth space weather features during Ascending phase of SC 25
Theogene Ndacyayisenga
Jean Uwamahoro
Jean Claude Uwamahoro
Rabiu Babatunde
Daniel Okoh
Kantepalli Sasikumar Raja
Christian Kwisanga
Christian Monstein
Abstract. Type II solar radio bursts are the signatures of particle acceleration caused by shock waves in the solar atmosphere and interplanetary space. Being electromagnetic radiation that travel at the speed of light, they can serve as ground observed data to provide early notice of incoming solar storm disturbances. An observational overview of 31 Type II bursts which occurred in the period between May 2021 to December 2022 is made. We analyzed associated parameters such as bandwidth, drift rates, starting frequency to evaluate their dynamical parameters such as the shock and Alfvén speeds to estimate the Alfvén Mach number as well as the coronal magnetic field strength using Rankine-Hugoniot relation. We also evaluated accompanying space weather implication in terms of ionospheric total electron content (TEC) enhancement. At heliocentric distance ∼ 1−2 R⊙, the shock and the Alfvén speeds are in the range 504–1301 km s−1 and 368–837 km s−1, respectively. The Alfvén Mach number is of the order of 1.2 ≤ MA ≤ 1.8 at the same heliocentric distance, and the magnetic field strength shows excellent consistency and could be fit with a single power-law distribution of the type B(r) = 6.56 r −3.92 G. The study finds that 15/31 type II radio bursts are associated with some aspects of space weather such as radio blackouts and/or polar cap absorption events, that are the signature of solar proton enhancement and solar energetic particle events. Observed and analyzed Type II events correlated well with observed ionospheric storm indicated by the TEC enhancement. The findings from this study indicate that through analysis of type II SRBs observed from the ground and their physical features characteristics, it is possible to monitor the current progress of solar cycle 25 and predict the intensity of associated space weather phenomena.
Theogene Ndacyayisenga et al.
Status: open (until 24 Apr 2023)
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RC1: 'Comment on egusphere-2023-201', Costas Alissandrakis, 28 Mar 2023
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The authors analysed 31 type II burst from e-CALLISTO observations during the period of May 2021 to December 2022 (ascending phase of the current solar cycle). Based on measurements of dynamic spectra, they estimated physical parameters of the associated shocks. They also examined associated X-ray flares and CMEs. The authors further examined in detail space whether effects of bursts on October 9, 2021 and during March 24 - April 3, 2022. They conclude that 15 out of their events were associated with space whether events.
Their results are new and interesting, hence the article merits publication after some improvements:
1. The authors should provide a table with the statistics of their results (range of values, average, rms), together with values from previous works for easy comparison.
2. Lines 107-109: please provided the values of the slope derived by Vršnak et al., 2002 and Umuhire et al., 2021.
3. The difference between the CME speed derived from the dynamic sectra and that of LASCO should be discussed further.
4. Figure 4: (a) please label the axes (b) add your own measurements (c) In the insert, replace equations with the model names.
Where does the "quiet Sun magnetic field model" come from?
5. Lines 200-220: Can you identify which TEC enhancements are associated with which type II?
6. The authors conclude that 15 out of their events were associated with space whether events. This is an important result and requires further discussion, preferebly in a separate section. For example, what were the differences between these 15 and the other type IIs? are there any observable type II characteristics that enhance the probability of space whether effects?
Finally, the authors may find interesting the review doi: 10.3389/fspas.2020.591075 on radio maesurements of the magnetic field.Citation: https://doi.org/10.5194/egusphere-2023-201-RC1 -
AC1: 'Reply on RC1', Theogene Ndacyayisenga, 29 Mar 2023
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On behalf of all Co-authors, I thank the referee for providing the comments on our manuscript. I hereby give the answers in the attached file.
Regards
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AC1: 'Reply on RC1', Theogene Ndacyayisenga, 29 Mar 2023
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Theogene Ndacyayisenga et al.
Theogene Ndacyayisenga et al.
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