A magnetosphere is that area of space, around a planet, that is controlled by the planet’s magnetic field. The shape of the Earth’s magnetosphere is the direct result of being blasted by solar wind. The solar wind compresses its sunward side to a distance of only 6 to 10 times the radius of the Earth.
A supersonic shock wave is created sunward of Earth called the bow shock. Most of the solar wind particles are heated and slowed at the bow shock and detour around the Earth in the magnetosheath. The solar wind drags out the night-side magnetosphere to possibly 1000 times Earth’s radius; its exact length is not known. This extension of the magnetosphere is known as the magnetotail. The outer boundary of Earth’s confined geomagnetic field is called the magnetopause. The Earth’s magnetosphere is a highly dynamic structure that responds dramatically to solar variations.
Also residing within the magnetosphere are areas of trapped charged particles; the inner and outer Van Allen Radiation Belts, the plasmasphere, and the plasmasheet.
The Sun and its atmosphere consist of several zones or layers. From the inside out, the solar interior consists of:
The Core – the central region where nuclear reactions consume hydrogen to form helium. These reactions release the energy that ultimately leaves the surface as visible light.
The Radiative Zone – extends outward from the outer edge of the core to base of the convection zone, characterized by the method of energy transport – radiation.
The Convection Zone – the outermost layer of the solar interior extending from a depth of about 200,000 km to the visible surface where its motion is seen as granules and supergranules.
The solar atmosphere is made up of:
The Photosphere – the visible surface of the Sun.
The Chromosphere – an irregular layer above the photosphere where the temperature rises from 6000°C to about 20,000°C.
A Transition Region – a thin and very irregular layer of the Sun’s atmosphere that separates the hot corona from the much cooler chromosphere.
The Corona – the Sun’s outer atmosphere.
Beyond the corona is the solar wind, which is actually an outward flow of coronal gas. The Sun’s magnetic fields rise through the convection zone and erupt through the photosphere into the chromosphere and corona. The eruptions lead to solar activity, which includes such phenomena as sunspots, flares, prominences, and coronal mass ejections.
Five researchers supported by NASA’s Living With a Star Program will join the 2023-2024 class of NASA’s Jack Eddy Postdoctoral Fellowship.
The early career PhDs, selected by the University Corporation for Atmospheric Research (UCAR)’s Cooperative Program for the Advancement of Earth System Science (CPAESS), will research interdisciplinary projects contributing to the field of heliophysics at a host institution for the next two years.
The Jack Eddy Postdoctoral Fellowship was founded in 2009 in honor of pioneering solar researcher John A. “Jack” Eddy. The program matches the fellows with experienced scientists at the host institutions to train the next generation of Sun-Earth researchers.
2023 NASA Jack Eddy Postdoctoral Fellowship Awardees
Peijin Zhang Host: Dr. Bin Chen of New Jersey Institute of Technology, Newark, NJ
PhD Institution: University of Science and Technology of China (USTC)
Proposal: Radio Imaging Spectroscopy for CMEs and CME-driven Shocks
Charlotte Waterfall Host: Dr. Georgia deNolfo of NASA’s Goddard Space Flight Center
PhD Institution: University of Manchester
Proposal: Bad News Travels Fast: Energetic Particle Transport in the Heliosphere
Robert Jarolim Host: Dr. Matthias Rempel at National Center for Atmospheric Research | High Altitude Observatory
PhD Institution: University of Graz
Proposal: Physics-informed Neural Networks for the Simulation of Solar Magnetic Fields
Devojyoti Kansabanik Host: Dr. Angelos Vourlidas at The Johns Hopkins University Applied Physics Laboratory
PhD Institution: National Centre for Radio Astrophysics, Tata Institute of Fundamental Research
Proposal: Remote Sensing of CME-entrained Magnetic Fields
Mei-Yun Lin Host: Dr. Andrew R. Poppe at the University of California, Berkeley
PhD Institution: University of Illinois, Urbana-Champaign
Proposal: From Ionosphere or Moon? A Comprehensive Study of Metallic Ions in the Magnetosphere
As Earth spins around the Sun, our planet’s slight tilt creates seasons. Now, research from two NASA space missions has found how the same tilt also influences seasonal differences in space weather – conditions in space produced by the Sun’s activity.
Space weather events produce the beautiful glow of the northern and southern lights, but, if intense enough, they can also endanger spacecraft and astronauts, disrupt radio communications, and even cause large electrical blackouts. Since space weather is created by particles and energy sent from the Sun, it varies with the Sun’s 11-year cycle of activity – the solar cycle. But space weather also varies on shorter timescales, such as seasonally and daily.
The new results, published in the journal Nature Communications, found that the seasonal differences are caused by a phenomenon known as the Kelvin-Helmholtz instability. This instability forms curling waves at the boundary between two regions – such as different layers of the atmosphere or between air and water – flowing at different speeds. These waves sometimes occur in Earth’s atmosphere, resulting in unique cloud formations that look like a series of crashing ocean waves. In space, these waves are composed of charged particles that are energized and pushed toward Earth, resulting in enhanced space weather effects.
The new findings confirm that Kelvin-Helmholtz waves are more commonly produced during the spring and fall equinoxes. During the equinoxes, Earth is not tilted toward or away from the Sun. As a result, the orientation of the Sun’s and Earth’s magnetic fields is ideal for forming Kelvin-Helmholtz waves. When Earth’s magnetic field is tilted at extremes toward or away from the Sun – such as during the summer and winter solstices – few Kelvin-Helmholtz waves are created.
“We have discovered that Kelvin-Helmholtz waves in the space around Earth are seasonal, which explains an important factor in the seasonal variation of space weather,” said the lead author on the new study, Shiva Kavosi, a researcher at Embry–Riddle Aeronautical University in Daytona Beach, Florida. “These waves are ubiquitous and can be found roughly 20 percent of the time around Earth, but after monitoring over an entire solar cycle, we now know there are more chances observing them during certain times of the year.”
To make the discovery, scientists used 11 years of data from NASA’s Time History of Events and Macroscale Interactions during Substorms, or THEMIS, mission, as well as four years of data from the Magnetospheric Multiscale, or MMS, mission. “The unique orbits and long period of observations by THEMIS made this discovery – which was first theorized in the 1970s – possible,” Kavosi said.
By better understanding how Kelvin-Helmholtz waves form due to Earth’s seasonal tilt, researchers can better forecast its effects and plan accordingly to ensure spacecraft and astronaut safety. “Additionally, space weather forecasters can now add this component to their models for better forecasting,” Kavosi said.
The CubeSat to Study Solar Particles (CuSP) launched as an Artemis I payload on 1:47 AM EST on Nov. 16, 2022. CuSP was deployed from its canister about eight hours after launch. Approximately two hours after deployment, CuSP transmissions were received by an Open Loop Receiver (OLR) operated by NASA’s Jet Propulsion Laboratory’s Radio Science Systems Group. The OLR recorded approximately 60 minutes of transmission from CuSP. Unfortunately, the CuSP team has not re-established contact with the CubeSat after the initial contact.
In the initial OLR contact (which was listening mode only) CuSP was operating mostly as expected. The solar arrays deployed, and they were stable and pointing at the Sun. However, anomalous software resets and temperature readings were reported during the contact.
NASA’s Deep Space Network (DSN) provided the mission team a downlink-only pass eight hours after deployment as well as a contact with CuSP 11 hours after deployment. CuSP radio transmissions were not detected during either of these DSN opportunities. No further radio transmissions have been received from CuSP during subsequent scheduled DSN contacts.
During the initial OLR contact period, CuSP experienced three software reboots. One ended during the start of the data collection period, one occurred in the middle of the data collection, and one occurred at the end. However, the OLR signal indicated that CuSP remained powered on after the last reboot.
An unexplained battery anomaly also occurred at the end of the initial data collection period. Two minutes prior to the end of the data collection period, one of the battery cells suddenly experienced a temperature spike – jumping from 34 degrees Celsius to more than 168 degrees Celsius in under a minute. The temperature of the anomalous cell subsequently increased from approximately 34 degrees Celsius to about 80 degrees Celsius before loss of contact.
The CuSP team is investigating the cause of the sudden battery temperature increase and working to find a solution. The team is also working to regain contact with the spacecraft.
CuSP was designed to be one of the first CubeSats to explore interplanetary space, the region around the Sun and planets of our solar system. This CubeSat’s objective is to study the solar wind particles and magnetic fields that stream from the Sun and the relationship of this solar wind to more energetic particles generated by solar activity.