Inference of the electron temperature in inertial confinement fusion implosions from the hard X‐ray spectral continuum. Issue 2 (10th September 2018)

• Record Type: Journal Article
• Authors: Kagan, Grigory; Landen, O.L.; Svyatskiy, D.; Sio, H.; Kabadi, N.V.; Simpson, R.A.; Gatu Johnson, M.; Frenje, J.A.; Petrasso, R.D.; Shah, R.C.; Joshi, T.R.; Hakel, P.; Weber, T.E.; Rinderknecht, H.G.; Thorn, D.; Schneider, M.; Bradley, D.; Kilkenny, J.
• Is Part Of: Contributions to plasma physics. Volume 59:Issue 2(2019)
• Page Start: 181
• Page End: 188
• Publication Date: 2018-09-10
• Subjects: high‐energy‐density -- inertial confinement -- x‐ray diagnostic; Plasma (Ionized gases) -- Periodicals; Electronic journals; 530.44
• DOI: 10.1002/ctpp.201800078
• Languages: English
• ISSNs: 0863-1042

Abstract

Abstract : Using the free‐free continuum self‐emission spectrum at photon energies above 15 keV is one of the most promising concepts for assessing the electron temperature in inertial confinement fusion (ICF) experiments. However, these photons are due to suprathermal electrons whose mean free path is much larger than the thermal one, making their distribution deviate from Maxwellian in a finite‐size hotspot. The first study of the free‐free X‐ray emission from an ICF implosion is conducted, accounting for the kinetic modifications to the electron distribution. These modifications are found to result in qualitatively new features in the hard X‐ray spectral continuum. Inference of the electron temperature as if the emitting electrons are Maxwellian is shown to give a lower value than the actual one.