Because your Vn − V0 will be your what you call high because V0 will be less, that is why that the middle conductor is higher than your what you call the electric field intensity at the surface of middle conductor is higher than the outer conductors.
V0 कमी असल्यामुळे Vn − V0 हा जास्त असेल, त्यामुळे बाजूच्या कंडक्टर पेक्षा मधल्या कंडक्टर मध्ये इलेक्ट्रिक फील्ड इन्टेन्सिटी जास्त असेल.