Energy spectrum of the Extreme Ultra-Violet (EUV) flux integrated over the solar disk. Solar EUV flux spectrum 136 Energy spectrum of the Ultra-Violet (UV) flux integrated over the solar disk. Solar UV flux spectrum 142 Observed variable - measurand (outer space) Vertical thickness of highly structured ion density in the F-region of the ionosphere. Spread F 122 Integrated Ultra-Violet (UV) flux over the solar disk. Solar UV flux 141 Map of magnitude and direction of the electric field at the solar surface (photosphere). Solar electric field 151 Random fluctuations of radio waves resulting of small scale variations of the ionospheric electron density in space and time. Ionospheric Scintillation 118 Image of the Sun in X-ray wavelengths. Solar X-ray image 149 Image of the Sun in white light. Solar white light image 159 Flux density of low-, medium-, and high-energy protons from the magnetosphere, the radiation belts or the interplanetary medium. Proton integral directional flux 520 Magnitude and direction of the Earth's electric field. Electric Field 115 Total number of ionized particles in a volume unit of ionospheric plasma. Ionospheric plasma density 120 Solar radio flux energy spectrum integrated over the solar disk. Solar radio flux spectrum 156 Flux density of low-, medium-, and high-energy electrons from the magnetosphere, the radiation belts or the interplanetary medium. Electron flux density 515 Flux density energy spectrum of low-, medium-, and high-energy electrons from the magnetosphere, the radiation belts or the interplanetary medium. Electron flux energy spectrum 104 Temperature of solar wind protons. Solar wind temperature 112 Integrated X-ray flux over the solar disk. Solar X-ray flux 147 2D image of the solar radio flux. Solar radio image 157 Integrated X-ray flux. X-ray flux 162 2019-11-21T09:08:28.449Z An alpha particle has positive charge and consists of two protons and two neutrons (the nucleus of a helium atom). Flux is the rate of flow through a reference surface, measured in particles per unit area. The directional flux is the flux limited to a certain solid angle as a function of the direction (pitch angle). Alpha particles integral directional flux 512 Vector velocity of solar wind plasma. Solar wind velocity 113 Flux density energy spectrum of neutrons from the Sun or as component of the cosmic radiation. Cosmic ray neutron flux spectrum 513 Altitude of the peak density in the ionospheric F2 layer. hmF2 126 Density of solar wind plasma. Solar wind density 409 Integrated radio flux over the solar disk. Solar radio flux 155 Integrated Ultra-Violet (UV) flux. UV flux 160 Observed variable - measurand (outer space) Extreme Ultra-Violet (EUV) image of the sky. EUV sky image 129 Integrated gamma-ray flux over the solar disk. Solar gamma-ray flux 152 Critical frequency of the F2 layer of the ionosphere. This critical frequency (f, in MHz) is associated with the electron density (Ne, in cm-3): f=9*10^-3*sqrt(Ne). foF2 124 Images of the Sun in the Ultra-Violet (UV) wavelengths. Solar UV image 143 Energy spectrum of the gamma-ray flux integrated over the solar disk. Solar gamma-ray flux spectrum 153 Flux density energy spectrum of low-, medium-, and high-energy protons from the magnetosphere, the radiation belts or the interplanetary medium, per unit solid angle. Proton differential directional flux 519 Vector magnetic field (3D) in the solar wind. The reference frame is Cartesian or Cylindrical with many different axis orientations. Important in Space Weather to monitor magnetic disturbances of the near earth environment. Interplanetary magnetic field 108 The highest ordinary-wave frequency reflected back from a sporadic E layer and observed by an ionosonde. foEs 123 Travelling radio-waves of solar, galactic and extragalactic origin, entering the Earth's environment. Radio-waves 133 Image of the solar corona surrounding the Sun. Solar coronagraphic image 150 Flux density of low-, medium-, and high-energy electrons from the magnetosphere, the radiation belts or the interplanetary medium, per unit solid angle. Electron integral directional flux 516 Map of 3D velocity of particles of the Solar atmosphere, significant of the Sun interior. Solar velocity fields 158 Flux density of heavy ions (heavier than Helium) per unit solid angle. Heavy ion differential directional flux 517 Flux density energy and mass spectrum of heavy ions ranging from Helium to Iron, per unit solid angle. Heavy ion angular flux energy and mass spectrum 106 Occurrence of fluorescence of the upper atmosphere through ionization by energetic charged particles accelerated by the Earth's magnetic field. Aurora 114 Velocity of bulk plasma or electrons (depending on measurement technique) as a function of altitude in the ionosphere. Ionospheric plasma velocity 121 X-ray image of the sky. X-ray sky image 164 Flux density energy spectrum of low-, medium-, and high-energy electrons from the magnetosphere, the radiation belts or the interplanetary medium, per unit solid angle. Electron differential directional flux 514 Measurement of the electrostatic charge of a satellite accumulated because of the environmental situation. Electrostatic charge 105 Integrated VIS (energy at visible wavelengths) flux over the solar disk Solar VIS flux 144 Energy spectrum of the integrated X-ray flux. X-ray flux spectrum 163 2 Radiative flux integrated over the EUV band. EUV flux 127 Images of the Sun in the Extreme Ultra-Violet (EUV) wavelengths in order to identify features such as filaments, active regions and coronal holes. Solar EUV image 137 Vector magnetic field (1D or 3D) at the solar surface (photosphere/chromosphere). Solar magnetic field 154 Ultra-Violet (UV) image of the sky. UV sky image 161 Image of the Sun in the K-line of Ca-II(393.4 nm). Solar Ca II-K image 134 Virtual height of the bottom of the ionospheric F-layer. h'F 125 Integrated Extreme Ultra-Violet (EUV) flux over the solar disk. Solar EUV flux 135 Flux density of heavy ions ranging from Helium to Iron. Heavy ion integral directional flux 518 Image of the Sun in the Hydrogen Lyman-alpha transition wavelength (121.6 nm). Solar Lyman-alpha image 140 Number of electrons between two points. Ionospheric Vertical Total Electron Content (VTEC) 119 Image of the interplanetary space between the Sun and Earth. Heliospheric image 132 Energy spectrum of the X-ray flux integrated over the solar disk. Solar X-ray flux spectrum 148 3-D field of the electron density in the ionosphere. Electron Density 116 Flux density energy and mass spectrum of heavy ions ranging from Helium to Iron. Heavy ion flux energy and mass spectrum 107 Attenuation of a radio wave passing through the lower ionosphere. Ionospheric Radio Absorption 117 Images of the Sun in the VIS (visible) wavelengths. Solar VIS image 146 Radiative flux integrated over the gamma-ray domain. Gamma-ray flux 130 Image of the Sun in the Hydrogen-alpha transition wavelength (656.3 nm). Solar H-alpha image 138 Energy spectrum of the radiative flux measured in the gamma-ray domain. Gamma-ray flux spectrum 131 Energy spectrum of the integrated VIS (energy at visible wavelengths) flux over the solar disk. Solar VIS flux spectrum 145 Alpha particles differential directional flux 511 Solar flux in the Hydrogen Lyman-alpha transition wavelength (121.6 nm). Solar Lyman-alpha flux 139 3D field of the dose rate of energetic particles Radiation Dose Rate 111 Energy spectrum of the radiative flux measured in the EUV band. EUV flux spectrum 128