Abstract
X-ray bursts observed for energies lower than 25 keV are usually interpreted as being produced by a thermal plasma with several million degrees of temperature.
A small number of events recorded at Arcetri by real time telemetry of SOLRAD 9 satellite agrees with a thermal interpretation and gives temperatures ranging between 10 × 106 and 30 × 106K and emission measures, ∫N 2e dV, between 1047 and 1048 cm−3.
An impulsive event recorded on January 7, 1969 shows an anomalous behaviour. In this case the emission has been attributed to bremsstrahlung radiation from electrons with a power law energy distribution dN = KE -γ dE. The values of the spectral index and of the emission measure are given.
A tentative interpretation of the event is suggested and the way to produce non-relativistic electrons with a power law energy distribution is investigated.
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Landini, M., Monsignori Fossi, B.C. & Pallavicini, R. Thermal and non-thermal soft X-ray bursts. Sol Phys 27, 164–173 (1972). https://doi.org/10.1007/BF00151780
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DOI: https://doi.org/10.1007/BF00151780