[1] During the EXL98 aircraft mission, sprites and blue jets were observed by narrow band cameras that measure the N 2 + 1NG (0,1) band at 4278Å and the N 2 2PG (0, 0) band at 3370Å . We discuss the observations ($1 km resolution), instrumental and atmospheric corrections, and altitude profiles of ionized (1NG) and neutral (2PG) emission observed during a specific sprite. The ratio of ionized-to-neutral emission indicates a relative enhancement of ion emission below 55 km. Characteristic electron energies (E Ch ) and electric fields (E ) are derived from these emission ratios using excitation rates computed from a model that solves the Boltzmann equation as a function of electric field. Up to 55km E follows the breakdown field (E k ) and E Ch is $2.2eV. Above 55 km E drops below E k and E Ch drops to $1.75eV near 60km.

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On August 9, 1981, a series of three rockets were launched over an air mass thunderstorm off the eastern seaboard of Virginia while simultaneous stratospheric and ground‐based electric field measurements were made. The conductivity was substantially lower at most altitudes than the conductivity profiles used by theoretical models. Direct current electric fields over 80 mV/m were measured as far away as 96 km from the storm in the stratosphere at 23 km altitude. No dc electric fields above 75 km altitude could be identified with the thunderstorm, in agreement with theory. However, vertical current densities over 120 pA/m² were seen well above the classical “electrosphere” (at 50 or 60 km). Frequent dc shifts in the electric field following lightning transients were seen by both balloon and rocket payloads. These dc shifts are clearly identifiable with either cloud‐to‐ground (increases) or intercloud (decreases) lightning flashes.

[1] The new constellation of radio beacons called Coherent Electromagnetic Radio Tomography (CERTO) will be available for measurements of ionospheric total electron content and radio scintillations. These beacons transmit unmodulated, phase-coherent waves, VHF, UHF, and L band frequencies. A fixed radio of 3/8 is used between successive frequencies. Total electron content (TEC) can be measured using the differential phase technique. The range between beacon and receiver is removed from the phase measurements, leaving a differential phase that is proportional to TEC. The three CERTO frequencies cover a wide range for determination of the radio scintillation effects caused by diffraction after propagation though ionospheric irregularities. All of the CERTO beacons are in low Earth orbit with inclinations ranging from equatorial to polar. Each satellite that carries CERTO has other plasma instruments that complement the beacon data. In addition, a Scintillation and Tomography Receiver in Space (CITRIS) instrument will be placed in orbit to detect signals from the CERTO beacons and from the array of 56 Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) VHF/S band radio beacons placed around the word by the French Centre National D'Etudes Spatiales. CITRIS will record ionospheric occultations and radio scintillations with a unique occultation and ground-to-space geometry. New algorithms have been developed for the multifrequency CERTO and CITRIS data to provide improved acquisition and analysis of TEC and scintillation data in ionospheric studies. The data from the CERTO constellation of beacons and receivers may be used to update space weather models.Citation: Bernhardt, P. A., and C. L. Siefring (2006), New satellite-based systems for ionospheric tomography and scintillation region imaging, Radio Sci., 41, RS5S23,

On-orbit firings of both liquid and solid rocket motors provide localized disturbances to the plasma in the upper atmosphere. Large amounts of energy are deposited to ionosphere in the form of expanding exhaust vapors which change the composition and flow velocity. Charge exchange between the neutral exhaust molecules and the background ions (mainly O + ) yields energetic ion beams. The rapidly moving pickup ions excite plasma instabilities and yield optical emissions after dissociative recombination with ambient electrons. Line-of-sight techniques for remote measurements rocket burn effects include direct observation of plume optical emissions with ground and satellite cameras, and plume scatter with UHF and higher frequency radars. Long range detection with HF radars is possible if the burns occur in the dense part of the ionosphere. The exhaust vapors initiate plasma turbulence in the ionosphere that can scatter HF radar waves launched from ground transmitters. Solid rocket motors provide particulates that become charged in the ionosphere and may excite dusty plasma instabilities. Hypersonic exhaust flow Manuscript