**Table 3:** Parameters of XMM-Newton observation of HDFN on June 1, 2001.
Observation geometry parameters
2001 June 01, $\lambda_{\rm XMM}$ = 251 $^{\circ }$
$\lambda_{\rm HDFN}$ = 148 $^{\circ }$ , $\beta_{\rm HDFN}$ = +57 $^{\circ }$
Solar Wind Parameters	High		Low
H⁺ flux SPFU^a	3.8		1.15
O⁷⁺/O⁶⁺ ^b	0.99		0.15
	Model 1^b		Model 2^c
	High	Low	High	Low
O⁸⁺/O⁷⁺	0.05::	1::	0.57	0.33
Line	Model Energy Flux (10^-9 erg cm^-2 sr^-1 s^-1)
O VII 0.57 keV	12.5	7.04	11.5	7.26
O VIII 0.65 keV	6.28	6.5	6.56	3.38

^a ACE SWEPAM data, SPFU = 2.6 10⁸ cm^-2 s^-1;
^b ACE SWICS data;
^c For these choices, see Sect. 5.