In this paper we report the detection of a newudheliospheric 2–3 kHz radio emission event by theudVoyager 1 spacecraft, the first to be observed during solarudcycle 23. The new event started on Nov. 1, 2002, and isudbelieved to be associated with a strong interplanetary shockudthat originated from a period of intense solar activity inudearly April 2001. Following previous interpretations ofudevents of this type, we assume that the radio emission isudproduced when the interplanetary shock interacted with theudheliopause, which is the boundary between the solar windudand the interplanetary medium. From the onset time of theudradio emission and a simple model for the propagationudspeed of the interplanetary shock, the heliocentric radialuddistance to the nose of the heliopause can be calculated, andudis about 153 to 158 AU, depending on the parameters used.udFrom computer simulations that give the ratio of the radialuddistance to the termination shock to the radial distance toudthe heliopause, the distance to the termination shock canudalso be calculated and is estimated to be about 101 toud108 AU.
展开▼
