IONOSPHERE DENSITIES & ELECTRIC CURRENTS
I had thought that the ionosphere has a net positive charge, but Perplexity.AI says otherwise, though it does mention electric currents.
Here's a simple table showing the approximate densities for each layer of the ionosphere:
Layer -- Height (km) -- Negative Density (cm⁻³) -- Positive Density (cm⁻³) -- Neutral Density (cm⁻³)
D ------------- 48-90 --------------- 10² - 10⁴ ------------- 10² - 10⁴ ----------------- 10¹³ - 10¹⁵
E ------------- 90-150 -------------- 10⁵ ------------------- 10⁵ ----------------------- 10¹¹ - 10¹³
F1 ----------- 150-220 ------------- 10⁵ - 10⁶ ------------- 10⁵ - 10⁶ ----------------- 10⁹ - 10¹¹
F2 ----------- 220-500+ ------------ 10⁶ ------------------- 10⁶ ----------------------- 10⁷ - 10⁹
Note: These values are approximate and can vary significantly based on time of day, season, solar activity, and latitude. The negative density primarily refers to electrons, while the positive density refers to ions. The neutral density decreases with altitude, while ionization generally increases.
None of the
ionospheric layers have a predominantly positive or negative charge. The ionosphere maintains quasi-neutrality throughout its layers, meaning the number of positively charged ions is approximately equal to the number of negatively charged electrons1. This balance of charges is a fundamental characteristic of ionospheric plasma.
1.
https://link.springer.com/referencework ... 4520-4_194
The electrons (from the solar wind) that cause auroras do not reach the ground. Instead, they collide with atoms and molecules in Earth's upper atmosphere, typically at an altitude of about 60-200 miles (100-320 kilometers) above the Earth's surface1,3. When these high-energy electrons interact with oxygen and nitrogen atoms in the ionosphere, they transfer their energy, causing the atoms to become excited4. As these excited atoms return to their normal state, they emit photons, creating the colorful light displays we see as auroras4.
After the collisions, the electrons lose most of their energy. Some of the lower-energy secondary electrons that result from these collisions may:
_Continue to interact with other atmospheric particles, causing further excitation and light emission.
_Be scattered in various directions, including back up towards space1.
_Gradually lose more energy through subsequent collisions and eventually become part of the ionosphere.
The electrons do not penetrate further down into the lower atmosphere or reach the Earth's surface due to the increasing density of the atmosphere at lower altitudes, which effectively stops their downward motion3.
1.
https://www.sciencedaily.com/releases/2 ... 185043.htm
2.
https://www.energy.gov/science/fes/arti ... fven-waves
3.
https://phys.org/news/2018-02-scientist ... thern.html
4.
https://www.space.com/aurora-origin-mys ... -electrons
The electrons from the solar wind that enter Earth's upper atmosphere do not directly push other electrons out of the atmosphere. Instead, the process is more complex and involves several mechanisms:
Trapping and redirection: Earth's magnetic field captures many of the incoming solar wind electrons, trapping them in the magnetosphere and redirecting them towards the polar regions1.
Energy transfer: When these high-energy electrons collide with atoms and molecules in the upper atmosphere (typically at altitudes of 100-320 km), they transfer their energy, causing excitation of atmospheric particles4.
Atmospheric interactions: After colliding with atmospheric particles, the electrons lose most of their energy. Some may:
Continue interacting with other atmospheric particles
Be scattered in various directions, including back towards space
Gradually lose more energy and become part of the ionosphere4
Ionospheric dynamics: The ionosphere, where these interactions occur, is a dynamic region. While some electrons may escape back to space, others are continuously being produced through ionization processes2.
Electric fields and currents: The interaction between solar wind and Earth's magnetic field creates electric fields and currents in the ionosphere, which can influence the movement of charged particles2,3.
1.
https://geo.libretexts.org/Bookshelves/ ... Atmosphere
2.
https://www.nasa.gov/missions/icon/stro ... con-finds/
3.
https://www.swsc-journal.org/articles/s ... 20043.html
4.
https://mountwashington.org/the-science-of-auroras/
Electric currents in the ionosphere can indeed discharge to satellites and other objects in space. This phenomenon is part of a complex system of space weather effects that can impact technology both in orbit and on Earth's surface.
The interaction between solar wind and Earth's magnetic field creates electric fields and currents in the ionosphere, which can lead to several effects:
Satellite charging: Satellites can accumulate electrical charge from the ionospheric plasma, potentially leading to electrostatic discharges4. These discharges can cause phantom commands, damage to electronics, loss of control, and even satellite failure2.
Internal charging: Highly energetic electrons (>2 MeV) can penetrate satellite components, causing internal charging and possible electric discharges. This can result in malfunctions or complete failure of satellites2.
Magnetosphere-ionosphere "lightning": Large-scale energy transfers between the magnetosphere and ionosphere can occur, lasting for hours and transferring hundreds to thousands of times more energy than terrestrial lightning5. This process is enhanced during solar storms and can affect satellites and other space-based technologies.
GPS and communication disruptions: The ionospheric currents and associated plasma disturbances can interfere with radio signals passing through the ionosphere, potentially disrupting GPS navigation and satellite communications3.
Ground-based infrastructure impacts: Strong ionospheric currents can induce currents in long conductors on Earth's surface, such as power lines and pipelines, potentially causing power system outages or pipeline corrosion2.
These effects highlight the importance of understanding and predicting ionospheric dynamics to protect our technological infrastructure both in space and on the ground3,5.
1.
https://www.swpc.noaa.gov/phenomena/ionosphere
2.
https://www.spaceweather.gc.ca/tech/index-en.php
3.
https://www.cnn.com/2024/08/02/science/ ... index.html
4.
https://www.nasa.gov/missions/icon/stro ... con-finds/
5.
https://www.nasa.gov/solar-system/revol ... -to-space/