## 3aPA2. Plasma diagnostics and sonoluminescence.

### Session: Wednesday Morning, December 4

### Time: 8:20

**Author: T. Lepoint**

**Location: Inst. Meurice--CERIA, 1, Av. E. Gryzon, 1070 Brussels, Belgium**

**Author: F. Lepoint-Mullie**

**Location: Inst. Meurice--CERIA, 1, Av. E. Gryzon, 1070 Brussels, Belgium**

**Author: R. Avni**

**Location: NRC Negev and BG Univ., Beer-Shiva 84190, Israel**

**Abstract:**

Plasma diagnostic techniques are applied to single- and multibubble
sonoluminescence (SBSL and MBSL). In the case of SBSL the electronic temperature
(T[inf e]) and density (N[inf e]) are deduced on basis of the spectrum of an Ar
bubble in water [the recording by R. Hiller et al., Science 226, 248 (1994)].
This analysis, based on the emission continuum, reveals that the intracavity
sonoluminescent medium behaves as a sparklike plasma highly charged with energy
(T[inf e]=20 000 K; N[inf e]=10[sup 25] m[sup -3]). In the case of MBSL (Ar
bubbles in water), the method of the ratio ``intensity of a line/intensity of
the adjacent continuum'' is used in order to determine T[inf e]. The higher the
ultrasonic frequency, the hotter the bubble interior is. Two scenarios are
analyzed (plasmas with a degree of ionization 1%) and the order of
magnitude of N[inf e] is estimated. The conditions associated with multibubble
systems appear to be of the same kind as those associated with SBSL, with a
lesser degree of intensity, however. The possibility is discussed that local
thermodynamic equilibrium (LTE) or partial LTE is reached. [Work supported by
F.N.R.S., Belgium.]

ASA 132nd meeting - Hawaii, December 1996