Waves is an experiment on the Juno spacecraft to study radio and plasma waves. Hz up to 40,000,000 Hz (40 MHz), and magnetic fields from 50 Hz to 20,000 Hz (20 kHz). It has two main sensors a dipole antenna and a magnetic search coil. The dipole antenna has two whip antenna's that extend 2.8 meters (110 inches/ 9.1 feet) and they are attached to the main body of the spacecraft. This sensor has been compared to a rabbit ears set-top TV antenna. The search coil is overall a mu metal rod 15 cm (6 in) length with a fine copper wire wound 10,000 times around it. There are also two frequency receivers that each cover certain bands. Data handling is done by two radiation hardened systems on a chip. The data handling units are located inside the Juno Radiation Vault. Waves was allocated 410 Mbits of data per science orbit.It is part of collection of various types of instruments and experiments on the spacecraft; Waves is oriented towards understanding fields and particles in Jupiter's magnetosphere. Waves is on board the unmanned Juno spacecraft, which was launched in 2011 and arrived at Jupiter in the summer of 2016. The major focus of study for Waves is Jupiter's magnetosphere, which if could be seen from Earth would be about twice the size of a full moon. It has a tear drop shape, and that tail extends away from the Sun by at least 5 AU (Earth-Sun distances). The Waves instrument is designed to help understand the interaction between Jupiter's atmosphere, its magnetic field, its magnetosphere, and to understand Jupiter's auroras. It is designed to detect radio frequencies from 50
Juno is a NASA space probe orbiting the planet Jupiter. It was built by Lockheed Martin and is operated by NASA's Jet Propulsion Laboratory. The spacecraft was launched from Cape Canaveral Air Force Station on August 5, 2011 (UTC), as part of the New Frontiers program. Juno entered a polar orbit of Jupiter on July 5, 2016, to begin a scientific investigation of the planet. After completing its mission, Juno will be intentionally deorbited into Jupiter's atmosphere.
Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Radio waves have frequencies as high as 300 gigahertz (GHz) to as low as 30 hertz (Hz). At 300 GHz, the corresponding wavelength is 1 mm, and at 30 Hz is 10,000 km. Like all other electromagnetic waves, radio waves travel at the speed of light in vacuum. They are generated by electric charges undergoing acceleration, such as time varying electric currents. Naturally occurring radio waves are emitted by lightning and astronomical objects.
In plasma physics, waves in plasmas are an interconnected set of particles and fields which propagate in a periodically repeating fashion. A plasma is a quasineutral, electrically conductive fluid. In the simplest case, it is composed of electrons and a single species of positive ions, but it may also contain multiple ion species including negative ions as well as neutral particles. Due to its electrical conductivity, a plasma couples to electric and magnetic fields. This complex of particles and fields supports a wide variety of wave phenomena.
On June 24, 2016 the Waves instrument recorded Juno passing across Jupiter's magnetic field's bow shock.It took about two hours for the unmanned spacecraft to cross this region of space. On June 25, 2016 it encountered the magnetopause. Juno would go on to enter Jupiter's orbit in July 2016. The magnetosphere blocks the charged particles of the solar wind, with the number of solar wind particles Juno encountered dropping 100-fold when it entered the Jovian magnetosphere. Before Juno entered it, it was encountering about 16 solar wind particles per cubic inch of space.
The magnetopause is the abrupt boundary between a magnetosphere and the surrounding plasma. For planetary science, the magnetopause is the boundary between the planet's magnetic field and the solar wind. The location of the magnetopause is determined by the balance between the pressure of the dynamic planetary magnetic field and the dynamic pressure of the solar wind. As the solar wind pressure increases and decreases, the magnetopause moves inward and outward in response. Waves along the magnetopause move in the direction of the solar wind flow in response to small-scale variations in the solar wind pressure and to Kelvin–Helmholtz instability.
The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between 0.5 and 10 keV. Embedded within the solar-wind plasma is the interplanetary magnetic field. The solar wind varies in density, temperature and speed over time and over solar latitude and longitude. Its particles can escape the Sun's gravity because of their high energy resulting from the high temperature of the corona, which in turn is a result of the coronal magnetic field.
There is various other antenna on Juno including the communication antennas and the antenna for the Microwave Radiometer.
Two other instruments help understand the magnetosphere of Jupiter, Jovian Auroral Distributions Experiment (JIRAM) and Magnetometer (MAG) instrument.The JEDI instrument measures higher energy ions and electrons and JADE lower energy ones, they are complementary. Another object of study is plasma generated by volcanism on Io (moon) and Waves should help understand that phenomenon also.
The magnetosphere of Jupiter is the cavity created in the solar wind by the planet's magnetic field. Extending up to seven million kilometers in the Sun's direction and almost to the orbit of Saturn in the opposite direction, Jupiter's magnetosphere is the largest and most powerful of any planetary magnetosphere in the Solar System, and by volume the largest known continuous structure in the Solar System after the heliosphere. Wider and flatter than the Earth's magnetosphere, Jupiter's is stronger by an order of magnitude, while its magnetic moment is roughly 18,000 times larger. The existence of Jupiter's magnetic field was first inferred from observations of radio emissions at the end of the 1950s and was directly observed by the Pioneer 10 spacecraft in 1973.
Jovian Auroral Distributions Experiment (JADE) is an instrument that detects and measures ions and electrons around the a spacecraft. It is a suite of detectors on the Juno Jupiter orbiter. JADE includes JADE-E, JADE-I, and the EBox. JADE-E and JADE-I are sensors that are spread out on the spacecraft, and the EBox is located inside the Juno Radiation Vault. EBox stands for Electronics Box. JADE-E is for detecting electrons from 0.1 to 100 keV, and there are three JADE-E sensors on Juno. JADE-I is for detecting ions from 5 eV to 50 keV. It is designed to return data in situ on Jupiter's auroral region and magnetospheric plasmas, by observing electrons and ions in this region. It is primarily focused on Jupiter, but it was turned on in January 2016 while still en route to study inter-planetary space.
Magnetometer (MAG) is the name of an instrument suite on the Juno orbiter for planet Jupiter. The MAG instrument includes both the Fluxgate Magnetometer (FGM) and Advanced Stellar Compass (ASC) instruments. There two sets of MAG instrument suites, and they are both positioned on the far end of three solar panel array booms. Each MAG instrument suite observes the same swath of Jupiter, and by having two sets of instruments, determining what signal is from the planet and what is from spacecraft is supported. Avoiding signals from the spacecraft is another reason MAG is placed at the end of the solar panel boom, about 10 m and 12 m away from the central body of the Juno spacecraft.
A primary objective of the Juno mission is to explore the polar magnetosphere of Jupiter. While Ulysses briefly attained latitudes of ~48 degrees, this was at relatively large distances from Jupiter (~8.6 RJ). Hence, the polar magnetosphere of Jupiter is largely uncharted territory and, in particular, the auroral acceleration region has never been visited. ...
Another issue that came up in 2002, was when Chandra determined with its high angular resolution that X-rays were coming from Jupiter's poles.Einstein Observatory and Germany's ROSAT previously observed X-rays from Jupiter. The new results by Chandra, which took the observations during December 2000, showed X-rays coming from the magnetic north pole not the aurora. Roughly every 45 minutes Jupiter sends out a multi-gigawatt X-ray pulse, and this is synchronized with an emission in radio at 1 to 200 kHz. Galileo orbiter and Ulysses solar orbiter picked up the radio emissions every 45 minutes. The radio emissions were discovered before the X-rays, they have been detected since the 1950s, and there is even Citizen astronomer project orchestrated by NASA called Radio Jove for anyone to listen to Jupiter's radio signals. Kilometric radio radiation was not detected until the Voyager flybys of Jupiter in the late 1970s. Two candidates for the source of the X-rays are particles of Solar wind or from Io.
The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space telescope launched on STS-93 by NASA on July 23, 1999. Chandra is sensitive to X-ray sources 100 times fainter than any previous X-ray telescope, enabled by the high angular resolution of its mirrors. Since the Earth's atmosphere absorbs the vast majority of X-rays, they are not detectable from Earth-based telescopes; therefore space-based telescopes are required to make these observations. Chandra is an Earth satellite in a 64-hour orbit, and its mission is ongoing as of 2019.
Einstein Observatory (HEAO-2) was the first fully imaging X-ray telescope put into space and the second of NASA's three High Energy Astrophysical Observatories. Named HEAO B before launch, the observatory's name was changed to honor Albert Einstein upon its successfully attaining orbit.
X-rays make up X-radiation, a form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (3×1016 Hz to 3×1019 Hz) and energies in the range 100 eV to 100 keV. X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays. In many languages, X-radiation is referred to as Röntgen radiation, after the German scientist Wilhelm Röntgen, who discovered it on November 8, 1895. He named it X-radiation to signify an unknown type of radiation. Spelling of X-ray(s) in the English language includes the variants x-ray(s), xray(s), and X ray(s).
Waves was developed at the University of Iowa, and the experiment is led by a research scientist there.
The University of Iowa is a public research university in Iowa City, Iowa. Founded in 1847, it is the oldest and the second largest university in the state. The University of Iowa is organized into 11 colleges offering more than 200 areas of study and seven professional degrees.
There are two main sensors for Waves, and these field signals to the frequency receivers.Both sensors are attached to main spacecraft body.
The MSC is made of a rod of Mu-metal (a ferromagnetic alloy of nickel and iron) wrapped in fine copper wire.
There are two frequency receivers that each cover certain bands, a high band and a low band, which in turn has different receiving sections.The receivers are housed in the Juno Radiation Vault along with other electronics.
All outputs are sent to the Data Processing Unit (DPU)
The output from the frequency receivers is in turn processed by the Juno DPU.The DPU has two microprocessors that use field programmable gate arrays are they are both system on chip designs. The two chips:
The DPU sends data to the main Juno computer for communication with Earth.The electronics are in the Juno Radiation Vault along with the receivers.
Waves has detected radio emissions from the Jupiter auroras, the most powerful known in the Solar System to date.
Galileo was an American unmanned spacecraft that studied the planet Jupiter and its moons, as well as several other Solar System bodies. Named after the Italian astronomer Galileo Galilei, it consisted of an orbiter and an entry probe. It was delivered into Earth orbit on October 18, 1989 by Space ShuttleAtlantis. Galileo arrived at Jupiter on December 7, 1995, after gravitational assist flybys of Venus and Earth, and became the first spacecraft to orbit Jupiter. It launched the first probe into Jupiter, directly measuring its atmosphere. Despite suffering major antenna problems, Galileo achieved the first asteroid flyby, of 951 Gaspra, and discovered the first asteroid moon, Dactyl, around 243 Ida. In 1994, Galileo observed Comet Shoemaker–Levy 9's collision with Jupiter.
The ionosphere is the ionized part of Earth's upper atmosphere, from about 60 km (37 mi) to 1,000 km (620 mi) altitude, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an important role in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on the Earth. The region below the ionosphere is called neutral atmosphere, or neutrosphere.
A solar flare is a sudden flash of increased brightness on the Sun, usually observed near its surface and in close proximity to a sunspot group. Powerful flares are often, but not always, accompanied by a coronal mass ejection. Even the most powerful flares are barely detectable in the total solar irradiance.
A whistler is a very low frequency or VLF electromagnetic (radio) wave generated by lightning. Frequencies of terrestrial whistlers are 1 kHz to 30 kHz, with a maximum amplitude usually at 3 kHz to 5 kHz. Although they are electromagnetic waves, they occur at audio frequencies, and can be converted to audio using a suitable receiver. They are produced by lightning strikes where the impulse travels along the Earth's magnetic field lines from one hemisphere to the other. They undergo dispersion of several kHz due to the slower velocity of the lower frequencies through the plasma environments of the ionosphere and magnetosphere. Thus they are perceived as a descending tone which can last for a few seconds. The study of whistlers categorizes them into Pure Note, Diffuse, 2-Hop, and Echo Train types.
Helios-A and Helios-B are a pair of probes launched into heliocentric orbit for the purpose of studying solar processes. A joint venture of West Germany's space agency DFVLR and NASA, the probes were launched from Cape Canaveral Air Force Station, Florida, on December 10, 1974, and January 15, 1976, respectively. Built by the main contractor Messerschmitt-Bölkow-Blohm, they were the first spaceprobes built outside both the United States and the Soviet Union to leave Earth orbit.
The magnetosphere of Saturn is the cavity created in the flow of the solar wind by the planet's internally generated magnetic field. Discovered in 1979 by the Pioneer 11 spacecraft, Saturn's magnetosphere is the second largest of any planet in the Solar System after Jupiter. The magnetopause, the boundary between Saturn's magnetosphere and the solar wind, is located at a distance of about 20 Saturn radii from the planet's center, while its magnetotail stretches hundreds of Saturn radii behind it.
The Global Geospace Science (GGS) Wind satellite is a NASA science spacecraft launched on November 1, 1994, at 09:31 UTC, from launch pad 17B at Cape Canaveral Air Force Station (CCAFS) in Merritt Island, Florida, aboard a McDonnell Douglas Delta II 7925-10 rocket. Wind was designed and manufactured by Martin Marietta Astro Space Division in East Windsor, New Jersey. The satellite is a spin-stabilized cylindrical satellite with a diameter of 2.4 m and a height of 1.8 m.
Dynamics Explorer was a NASA mission, launched on August 3, 1981 and terminated on February 28, 1991. It consisted of two unmanned satellites, DE-1 and DE-2, whose purpose was to investigate the interactions between plasmas in the magnetosphere and those in the ionosphere. The two satellites were launched together into polar coplanar orbits, which allowed them to simultaneously observe the upper and lower parts of the atmosphere.
Energetic neutral atom (ENA) imaging, often described as "seeing with atoms", is a technology used to create global images of otherwise invisible phenomena in the magnetospheres of planets and throughout the heliosphere, even to its outer boundary. This constitutes the far-flung edge of the solar system.
JunoCam is the visible-light camera/telescope of the Juno Jupiter orbiter, a NASA space probe launched to the planet Jupiter on 5 August 2011. It was built by Malin Space Science Systems. The telescope/camera has a field of view of 58 degrees with four filters. The camera is run by the JunoCam Digital Electronics Assembly (JDEA) also made by MSSS. It takes a swath of imaging as the spacecraft rotates; the camera is fixed to the spacecraft so as it rotates, it gets one sweep of observation.
The JUpiter ICy moons Explorer (JUICE) is an interplanetary spacecraft in development by the European Space Agency (ESA) with Airbus Defence and Space as the main contractor. The mission is being developed to visit the Jovian system and is focused on studying three of Jupiter's Galilean moons: Ganymede, Callisto, and Europa all of which are thought to have significant bodies of liquid water beneath their surfaces, making them potentially habitable environments.
JEDI, is an instrument on the Juno spacecraft orbiting planet Jupiter. JEDI coordinates with the several other space physics instruments on the Juno spacecraft to characterize and understand the space environment of Jupiter's polar regions, and specifically to understand the generation of Jupiter's powerful aurora. It is part of a suite of instruments to study the magnetosphere of Jupiter. JEDI consists of three identical detectors that use microchannel plates and foil layers to detect the energy, angle, and types of ion within a certain range. It can detect electrons between 40 and 500 keV, and hydrogen and oxygen from a few tens of keV to less than 1000 keV. JEDI uses radiation hardened Application Specific Integrated Circuits (ASIC)s. JEDI was turned on in January 2016 while still en route to Jupiter to also study interplanetary space. JEDI uses solid state detectors (SSD's) to measure the total energy (E) of both the ions and the electrons. The MCP anodes and the SSD arrays are configured to determine the directions of arrivals of the incoming charged particles. The instruments also use fast triple coincidence and optimum shielding to suppress penetrating background radiation and incoming UV foreground.
UVS, known as the Ultraviolet Spectrograph or Ultraviolet Imaging Spectrometer is the name of an instrument on the Juno orbiter for Jupiter. The instrument is an imaging spectrometer that observes the ultraviolet range of light wavelengths, which is shorter wavelengths than visible light but longer than X-rays. Specifically, it is focused on making remote observations of the aurora, detecting the emissions of gases such as hydrogen in the far-ultraviolet. UVS will observes light from as short a wavelength as 70 nm up to 200 nm, which is in the extreme and far ultraviolet range of light. The source of aurora emissions of Jupiter is one of the goals of the instrument. UVS is one of many instruments on Juno, but it is in particular designed to operate in conjunction with JADE, which observes high-energy particles. With both instruments operating together, both the UV emissions and high-energy particles at the same place and time can be synthesized. This supports the Goal of determining the source of the Jovian magnetic field. There has been a problem understanding the Jovian aurora, ever since Chandra determined X-rays were coming not from, as it was thought Io's orbit but from the polar regions. Every 45 minutes an X-ray hot-spot pulsates, corroborated by a similar previous detection in radio emissions by Galileo and Cassini spacecraft. One theory is that its related to the solar wind. The mystery is not that there are X-rays coming Jupiter, which has been known for decades, as detected by previous X-ray observatories, but rather why with the Chandra observation, that pulse was coming from the north polar region.
Microwave Radiometer (MWR) is an instrument on the Juno orbiter sent to planet Jupiter. MWR is a multi-wavelength microwave radiometer for making observations of Jupiter's deep atmosphere. MWR can observe radiation from 1.37 to 50 cm in wavelength, from 600 MHz to 22 GHz in frequencies. This supports its goal of observing the previously unseen atmospheric features and chemical abundances hundreds of miles/km into Jupiter's atmosphere. MWR is designed to detect six different frequencies in that range using separate antennas.
The Plasma Instrument for Magnetic Sounding (PIMS) is a Faraday cup based instrument that will fly on board the Europa Clipper orbiter to explore Jupiter's moon Europa. PIMS will measure the plasma that populates Jupiter's magnetosphere and Europa's ionosphere.
Plasma Wave Subsystem, abbreviated PWS, is an instrument that is on board the Voyager 1 and Voyager 2 unmanned probes of the Voyager program. The device is 16 channel step frequency receiver and a low-frequency waveform receiver that can measure electron density. The PWS uses the two long antenna in a V-shape on the spacecraft, which are also used by another instrument on the spacecraft. The instrument recorded data about the Solar system's gas giants, and about the outer reaches of the Heliosphere, and beyond. In the 2010s the PWS was used to play the "sounds of interstellar space" as the spacecraft can sample the local interstellar medium after they departed the Sun's heliosphere. The heliosphere is a region essentially under the influence of the Sun's solar wind, rather than the local interstellar environment, and is another way of understanding the Solar system in comparison to the objects gravitationally bound around Earth's Sun.