Podcast
Questions and Answers
What are magnetospheric substorms and storms indicators of?
What are magnetospheric substorms and storms indicators of?
geomagnetic activity
Which geomagnetic index is commonly used to study substorms?
Which geomagnetic index is commonly used to study substorms?
- Ap index
- Kp index
- AE index (correct)
- Dst index
Magnetic storms are driven directly by solar drivers such as coronal mass ejections and flares.
Magnetic storms are driven directly by solar drivers such as coronal mass ejections and flares.
True (A)
What is the disturbance storm time index (Dst) used to characterize?
What is the disturbance storm time index (Dst) used to characterize?
What role does magnetic reconnection play in the magnetosphere?
What role does magnetic reconnection play in the magnetosphere?
The solar wind energy input during substorms is approximately _____ W.
The solar wind energy input during substorms is approximately _____ W.
The duration of magnetospheric substorms typically lasts for about _____ hours.
The duration of magnetospheric substorms typically lasts for about _____ hours.
What happens during substorms in terms of energy release?
What happens during substorms in terms of energy release?
During which event did the intense geomagnetic storms discussed in the talk occur?
During which event did the intense geomagnetic storms discussed in the talk occur?
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Study Notes
Overview of Magnetic Storms and Substorms
- Magnetic storms and substorms reflect geomagnetic activity influenced by solar phenomena.
- Storms are characterized by the Dst index, while substorms are identified using the AE index.
Key Characteristics
- Intense magnetic storms can be linked to specific events such as those on October 29-31 and November 20-21, 2003.
- Magnetospheric substorms occur due to disturbances in the magnetosphere triggered by solar wind.
Energy Transfer Mechanism
- Magnetic reconnection is crucial for transferring energy from the solar wind to the magnetosphere.
- The interplanetary magnetic field's southward orientation enhances magnetic reconnection, leading to increased auroral activity.
Energy Input Comparison
- Energy input to the magnetosphere during substorms averages around 10^11 watts.
- Moderate magnetic storms receive approximately 10^13 watts from solar wind.
Substorm Dynamics
- Substorms typically last from one hour to a few hours.
- A rapid release of stored energy in the magnetotail occurs, producing energetic particles and strong plasma flows.
- Plasma flows can reach speeds of 100-1000 km/s, leading to intense auroras.
Effects on Earth's Environment
- Geomagnetic storms disturb the Earth's magnetic field through intensified field-aligned currents and auroral electrojets.
- Adverse effects on telecommunications, navigation systems, and spacecraft operations are associated with intense geomagnetic storms.
Observations and Data
- Aurora phenomena observed at Indian Antarctic station Maitri highlight the impact of geomagnetic events.
- Geomagnetic storms can significantly affect technology and infrastructure on Earth.
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