Seminars
Since the Voyager mission flybys in 1979, we have known Jupiter moon Io to be extremely volcanically active as well as to be the main source of plasma in the vast magnetosphere of Jupiter. While the volcanic activity is generally dynamic and variable, the Jupiter magnetospheric plasma environment is stable on timescales from days to months. However, various observations suggest that occasionally (roughly 1-2 times per decade) the plasma environment undergoes major transient changes over several
weeks, apparently overcoming any stabilizing mechanisms.
I review the current knowledge on Io’s volcanic activity, atmosphere, and the magnetospheric neutral and plasma environment in view of their roles in the mass transfer from Io to the plasma torus and magnetosphere. At the end, I will briefly discuss what current and future space missions (Juno, JUICE, Europa Clipper) might contribute to address this topic.
- Enrolled students: 1
The law of conservation of energy states that energy is neither created nor destroyed; it can only transform into different forms or transfer from one place to another. This principle is crucial in understanding many natural phenomena, including those occurring within Earth's magnetosphere. A significant portion of the magnetospheric energy input originates from the Sun, primarily through solar wind, Coronal Mass Ejections (CMEs), and solar flares. These energetic solar events influence the magnetosphere, leading to various phenomena, including the generation of waves.
Waves are one of the key effects driven by space weather and terrestrial conditions. Different types of waves are involved, including atmospheric waves such as planetary waves, tides, and Atmospheric Gravity Waves (AGWs). AGWs are particularly important in influencing ionospheric behavior and can lead to disturbances known as Travelling Ionospheric Disturbances (TIDs). These disturbances are often the result of processes such as Perkins Instability and other mechanisms that generate AGWs. The interaction between AGWs and the ionosphere plays a key role in the formation and propagation of TIDs.
Groups of AGWs and TIDs are discussed in detail, highlighting their interactions and how they contribute to the overall dynamics of the ionosphere. Additionally, the presentation explores other mechanisms that can give rise to TIDs, such as the impact of geomagnetic storms, lightning, and other space weather phenomena.
At the conclusion of the presentation, we explore the significant impacts of TIDs on High Frequency (HF) communications. These disturbances can affect radio signal propagation, leading to communication outages, signal degradation, and interference. Understanding the behavior of TIDs is essential for predicting and mitigating their effects on HF communication systems, which are critical for global communication networks, particularly in remote and military applications.
- Enrolled students: There are no students enrolled in this course.